Aleppo Pine Blight

About this time of year we begin to see browning of Aleppo pine branch tips on some trees. I hope to reassure you that, in most cases, there is nothing to worry about.

Aleppo pines can start to look pretty ragged during the colder parts of the year with brown patches scattered throughout the tree canopy.  In most cases, this is a reversible condition that should get better as the weather warms in the spring.  The effect can often be minimized by making sure that the tree gets good care.

The Aleppo pine is a good choice for the low desert areas of Southern Arizona because it is well adapted to our harsh climate and alkaline soils.  It attracts few, if any insect pests and it has no major diseases to shorten its life.  It is a fast-growing tree and it provides good shade for our hot, summer days.  It has been, and continues to be, a landscape stalwart in this area.

It does, however, have one disconcerting tendency.  The needles close to the tips of some branches during the cool winter months can turn an unsightly brown.  Sometimes the needles stay flexible and turn green again as the weather warms.  Sometimes the needles will actually die, turn brittle and fall off; but the twigs and branches that support the needles usually stay green and will eventually regrow new needles.

The browning condition is referred to as Aleppo pine blight.  The disease is not caused by fungi, bacteria or insects.  It is a weather-induced shock to tender, actively growing needles at the tips of the branches.  Since not every branch of the tree is affected, the browning effect gives the tree a part-green, part brown appearance that can lead one not familiar with the condition to believe that the tree is dying.  In reality trees rarely, if ever, die of Aleppo pine blight.

With all of the recent publicity given to the bark beetle devastation in Northern Arizona pine forests, it is logical to assume that the browning of Aleppo pines is somehow related to these beetles.  You can ease your minds on that matter. 

First of all, the bark beetles of Northern Arizona do not like the desert climate.  It is too hot here for them.  Second, if the damage now seen in Aleppo pines were caused by bark beetles, the twigs and branches would not remain green to produce new needles in the spring.  Third, the damage would not be spotty on the tree.  Bark beetles cause a rapid decline and eventual death of the entire tree. 

While the specific cause of Aleppo pine blight is still unclear, there are a couple of theories that have been proposed.  One states that the effect develops when there is not enough time between warm and cold weather in the fall and winter to allow sufficient winter dormancy to develop.  Certainly, the variable weather that we have been experiencing in past years lends support to this theory.  One week, the fall temperatures can be in the eighties and nineties; the next in the low forties and even in the thirties.  This transition is hard on plants.

Another theory blames the browning of the needles on a previous stress for water and nutrients.  Most plants under stress often shut down part or all of the plant for a time until conditions for growth and development are better.  A good example of this is the ocotillo.  When warm, dry weather arrives, the ocotillo sheds its tender leaves and goes to sleep.  Once  the rains come again, the plant reawakens, puts on new leaves and begins a new growth cycle.  Aleppo pine blight may be an example of a similar response by the Aleppo pine.  The tree may simply not have enough strength to support the many needles on all of the branches of the tree, and the browning may be a move by the tree to cut back to what it can sustain.

Symptoms of Aleppo pine blight are noticeably striking.  Affected foliage suddenly dehydrates, turns whitish green, then brown, usually in the cool months of the year.  A few green needles or parts of an individual needle may survive in the midst of the blighted ones.  Some defoliation may occur and tree sap may sometimes seep from the blighted twigs.  In the more severe cases, some twig die-back may actually result.

The blight may be triggered in part by night-day temperature extremes and drying winds, since the symptoms usually show up on the sun-exposed, windward tops and sides of the trees.  Most affected branches survive this peculiar affliction and readily replace the brown needles in late spring and early summer as the trees begin their new growing season.

A good way to diagnose this particular problem is to bend the affected needles and twigs.  If the needles and twigs are brown beneath the bark and become brittle so that they snap easily, it may be that the tree is experiencing dehydration and death of some of its parts due to severe water stress and heat injury.  If the needles are still flexible, or only a few are brittle, the problem may simply be the Blight. 

While the symptoms of Aleppo pine blight may never be completely eradicated, there are a few steps that can be taken to ease the problem in most trees.  Make sure that the tree gets at least a monthly deep irrigation throughout the entire root zone of the tree and apply  a nitrogen fertilizer at least twice a year to support new growth.  

There is a slight chance that browning of needles and death of twigs may be related to a more serious disorder, such as root rot generally associated with too much water, but that condition is rare.  It is important, whenever there is a condition of which we are not sure, to always be vigilant and watch for signs that the problem is getting worse.  The Aleppo, however, is a pretty resilient plant and usually does not give its owners too much to worry about.

If you have questions, you can reach one of the Master Gardeners at the Cooperative Extension office, 820 E. Cottonwood Lane, Building C, in Casa Grande.  The telephone is (520) 836-5221.  The author’s email address is gibsonrd@ag.arizona.edu.

The University of Arizona is an equal opportunity, affirmative action institution.  The University does not discriminate on the basis of race, color, religion, sex, national origin, age, disability, veteran status, or sexual orientation in its programs and activities.

Rick Gibson
Extension Agent, Agriculture
University of Arizona Cooperative Extension
820 E. Cottonwood Lane, Building C
Casa Grande, Arizona 85222
Voice:    (520) 836-5221
Fax:    (520) 836-1750
email:    gibsonrd@ag.arizona.edu

Pruning Trees along Public Streets

If your tree is growing next to a public walkway or street, you will want to keep it pruned for the safety and protection of others.

Trees growing along streets, sidewalks, and other public areas are governed by city, county, and state codes that are created and put into force to protect the general public.  Trees growing in or along public areas can cause safety issues if they are not correctly maintained.  Acting as good citizens, it is important that we do our part to keep our homes and communities safe for others.

While pruning for public safety is essential, it must be done correctly for no other reason than to maintain the long life and health of the plant.  Improper pruning opens up channels for disease and insect infestation and destroys the natural form of the plant.  Perennial plants store their extra food supplies created through the process of photosynthesis not only in the roots but also in the wood of the trunk and branches.  Heavy pruning removes large quantities of wood and energy needed by the plant.  Weakened trees become more susceptible to insects and diseases.  All of these can cause safety issues in their own right.

Normal pruning techniques require the removal of dead, damaged, or misplaced branches in that order.  In so doing, we try to keep a tree or shrub uniform in appearance on all sides of the plant to mimic what the plant would look like if it were growing wild.  We strive to maintain its natural form.   

I would be the first to agree that pruning for safety might require a stretch of these normal rules of pruning.   Growing alongside a street or sidewalk, a tree or shrub might need to be altered on one side to accommodate pedestrian or vehicular traffic.  Hiding a stop sign, the plant may need to be thinned to allow visibility.  Please, even in these situations, there is no call to hack away at the plant willy-nilly and throw out completely the proven rules of pruning. 

Good pruning helps ensure good health.  If we are going to go through the expense of purchasing, planting, and caring for the plant in the first place, why throw all of that good hard cash out the window by massacring the poor thing?  There are ways to do the job without seriously damaging the plants.

Pruning for safety usually means cutting back trees and shrubs that may obscure the vision of drivers, scrape or scratch vehicles as they pass, or force pedestrians out into a street or road.  In these cases, selective cuts must be made to improve visibility and remove the chance of injury or damage.  Let’s review a few basic rules of pruning and how they might apply to situations where public safety might be an issue.

The easiest and best way to prevent problems later in the plant’s life is to begin the training process early.  Making cuts to young plants when the branches are pencil size and smaller is less stressful than cuts made to larger branches.  Allowing the canopy to develop naturally by removing entire branches that are growing in the wrong way early on will maintain the number of leaves necessary to store energy for the plant and at the same time push the growth in directions that will be less offensive to the public traveling nearby.  Then, as the plant matures, it is a simple matter to make small, less invasive, corrective cuts.

When working on mature trees, don’t just hack at the plant.  The most common but least advised way to meet height limits for trees is to simply hack off the branches at the desired height.  This is not a good idea because the stump ends of the branches are susceptible to insects and diseases.

One of the quickest ways to infect a tree with heart rot or provide an entry way for insects is to leave a blunt end of a cut branch.  Blunt ends and stubs, any cut end of a branch upon which one could hang a hat, almost always die back. Dead or dying wood emits an odor that attracts wood decaying insects like flat-headed wood borers and others.  Attracted to dead or dying wood, they enter in for a free lunch and then set up housekeeping, sometimes even penetrating down into healthy wood.  How can we avoid this?  Don’t leave blunt ends and stubs.

The correct procedure for making cuts is to follow the offending branch back to its point of attachment and make the cut there.  Any cut of a branch pencil size or greater should be made in this manner.  If possible try to force the remaining growth upward and out by retaining branches that grow in the proper direction above the mandated height limitations.  Don’t worry about applying a pruning sealant to the cut.  In our dry climate research has shown that they are not needed.

As you make your cuts it is important to remember to preserve the branch collar.  The branch collar is a swelling of tissue at the base of the branch or limb that is full of  actively dividing cells.  By leaving the collar, a pruning wound will cover and seal over faster than if the collar is cut away. 

We often refer to cuts that remove both the collar and the branch as a “flush cut.”  Flush cuts, or cuts that are made flush with the older branch or trunk, are unhealthy, weaken the branch, and should be avoided at all costs.  Where a branch collar cannot be identified, we look for the branch bark ridge, a ridge of bark between the two branches and then from the base line of that ridge estimate out a 45 degree angle and make our cut.  A cut at a 45 degree angle to the bark ridge should avoid a flush cut and not leave a stub.

So, let’s say that we have a fully mature tree with branches clearly hanging down too far into a roadway.  What do we do?  The first step is to take a good look at the tree and make a plan.  Start by looking at the top of the tree and work down.  Most trees have a central leader, a main trunk from which side branches emerge.  It is important to protect the leader because it will be the point of upward growth for the tree.  Next, study the lateral branches and especially those that hang out into the street.  Identify those branches that absolutely have to come out and those that with a little pruning can be retained and still meet the code limits.  Then, prune all offending branches back to their origin.

With all of this said however, many safety issues needing correction in the landscape can generally be traced back to improper plant selection and placement.  If we have done our homework, we will know that mesquite trees have the capacity to grow up to 30 feet tall and as many feet wide.  Knowing that, we can properly select a planting site where the tree will not later in life cause problems on rights-of-way.  While I hate to say it, a tree or shrub that cannot be trained properly for public safety may just have to be removed.

Human safety is of paramount importance in any landscape.  Correcting any situation that can lead to injury is important and helpful when done in the right way

If you have questions, you can reach one of the Master Gardeners at the Cooperative Extension office, 820 E. Cottonwood Lane, Building C, in Casa Grande, Arizona 85122.  The telephone is (520) 836-5221, extension 204. 

The University of Arizona is an equal opportunity, affirmative action institution.  The University does not discriminate on the basis of race, color, religion, sex, national origin, age, disability, veteran status, or sexual orientation in its programs and activities.

Rick Gibson
Extension Agent, Agriculture
University of Arizona Cooperative Extension
820 E. Cottonwood Lane, Building C
Casa Grande, Arizona 85222
Voice:    (520) 836-5221
Fax:    (520) 836-1750
email:    gibsonrd@ag.arizona.edu

Feeding Damage on Agave sp.

The feeding damage on the agave leaf shown in the photo is the latest of several similar examples that have come into the Cooperative Extension office here in Casa Grande, Arizona, USA.  The leaf shows hollowed out sections on the inner surfaces and missing sections at the leaf's margins.

The temptation, of course, is to blame an insect for the damage, but there are no known insects that would cause this kind of damage to agave species here in the Sonoran desert.  The agave snout weevil larva is a known pest on agave here but it is an internal feeder and causes an entirely different set of problems.  Typical agave snout weevil damage causes the drying and collapse of the entire plant.

The damage shown here is probably caused by a small mammal, such as a ground squirrel or more likely a small plant feeding rodent.  While we have not been able to positively identify the animal causing the damage through direct observation, we are fairly sure that we are on the right track.

Plants showing this kind of damage are typically younger and smaller plants, so it may be that as a plant ages and matures, the leaves become less attractive.  If we can get some growth on the plants, we should obtain relief from the feeding.

One way to protect the plant from further damage is to build a frame over the plant and drape the frame with bird netting.  Wire fencing is sometimes recommended to protect plants from vertebrate damages, and it works particularly well with rabbits, but fencing seems to be less effective against smaller animals because they tend to climb over the barrier.  Bird netting appears to work better, perhaps because they fear becoming entangled in the clingy mesh. As the plant matures, the netting can be removed.

If you would like to discuss this further, call one of our Master Gardener volunteers at 520.836.5221 extension 204. 

The University of Arizona is an equal opportunity, affirmative action institution.  The University does not discriminate on the basis of race, color, religion, sex, national origin, age, disability, veteran status, or sexual orientation in its programs and activities.

Rick Gibson
Extension Agent, Agriculture
University of Arizona Cooperative Extension
820 E. Cottonwood Lane, Building C
Casa Grande, Arizona 85122
Voice:    (520) 836-5221
Fax:    (520) 836-1750
email:    gibsonrd@ag.arizona.edu

Ten Signs That A Tree Is Planted In the Wrong Place

Planting a tree in a location where it will fail to thrive, or where it will become a nuisance, can be a costly mistake.

Trees, shrubs and bedding plants provide many benefits to a residential landscape, including beauty, shade and a welcoming feel to outdoor living areas.  A handsome, functional landscape also adds value to the home and can put extra money in the pocket when the home is sold later on.  In order to maximize these benefits, it is important to properly plan, install and care for the landscape.

Unfortunately, far too many mistakes are made at planting.  In horticultural terms, it is a mistake to plant a tree where soil or environmental conditions will not favor good growth, where it will eventually need regular and heavy corrective pruning or where it may need to be completely removed within a few years.

Heavy corrective pruning destroys the natural form and beauty of the tree and opens it up to possible infection by plant disease organisms and insect pests.  Removing and replacing a tree results in the loss of the plant’s immediate value.  It also means a loss of the valuable time required to bring the tree to maturity.  By taking the time to do the project right the first time, the owner or manager of a valuable landscape can save both time and money.

Here are ten common signs that a tree has been planted in the wrong place.  If you are getting ready to install a landscape, a good first step would be to take a drive or walk into any residential or commercial area and learn to recognize these mistakes. Then, as you plan your landscape, make sure that they do not show up in your yard.

Sign number one: the tree is growing into a power line.  Tree limbs growing into electrical lines strung from power poles can be dangerous hazards to people and property.  Maintenance crews regularly trim out branches that grow into and around these lines.  Trees that have been trimmed for safety often have their natural form, and their value, either seriously damaged or destroyed.  Many times these trees end up being removed completely.  When siting a tree, place it in a location where it will can grow in its natural form without danger of growing into power lines.

Sign number two: the tree branches grow into the street.  Planting a tree too close to the street will cause the tree eventually to spread its branches into a place where bicycle, car, and truck traffic will either hit, or swerve around, the branches.  In either case, the tree becomes a safety hazard that will need to be severely pruned or removed.

Sign number three: the tree limbs and branches grow over the fence into the neighbor’s yard.  If the neighbor doesn’t mind the tree or the shade that the tree provides, this may not be a problem.  More frequently than not, however, the people next door would prefer that a tree not invade their space.  The hassles, problems and potential conflicts that could occur are easily avoided  by planting the tree in a location where it will not cross property boundaries.

Sign number four: the tree branches rub on the exterior walls or the roof of the house.  Branches blowing too and fro in the wind can scrape and damage brick, paneled, or stucco walls.  They can also rip asphalt shingles or break tiles on the roof.  Plant the tree away from the home to avoid expensive repairs.

Sign number five: the trees grow into each other.  Trees planted too close together compete for water, air, nutrients and sunlight.  A lack of proper nutrition or sunlight will often stunt plants and weaken their trunks and branches. Branches that cross and rub against each other can easily be damaged and ruined.

Sign number six: the tree is damaging water, sewer, or natural gas lines.  Some trees have aggressive, fast-growing roots that can overpower and damage underground utility lines.  Sewer pipes are particularly vulnerable, for example, to the invasion of mulberry tree roots.  Depending upon the type of line, the damage can range from a mere frustration to one of real danger.  It is important to know where the lines are on the property, and avoid them.

Sign number seven: the trees shade out lawns and flower beds and make them unproductive.   Dense shade from large trees will often prevent lawn grasses, bedding plants, shrubs, vines and other trees from properly growing as they shade out their smaller competitors. 

Sign number eight: the tree is in a place where it can heave and buckle sidewalks and fences.  The roots of large trees, if they grow too close to the surface of the soil, can push up sidewalks and fences.  This type of structural damage can be difficult, as well as expensive, to repair.

Sign number nine: a caliche layer or structural hard spot in the soil causes the roots of trees to grow up close to the surface of the soil.  Shallow, improperly rooted trees can more easily blow over in a windstorm.  This problem can be avoided by checking the percolation of water through the soil prior to planting and by properly preparing the planting hole.

Sign number ten: the tree cannot be properly irrigated in a timely manner because water on the property is unavailable or is too expensive for the budget of the person paying the water bill.  Trees will become seriously damaged, or even die, if they do not receive the proper amount of water during the growing season.

Planting a tree in the wrong location is one of the more obvious and expensive mistakes that is all too commonly made during landscape planning and installation.  By taking the time to plan and install trees properly, major landscape mistakes can be avoided.  This will result in savings of both time and money.

If you have questions, you can reach one of the Master Gardeners at the Cooperative Extension office, 820 E. Cottonwood Lane, Building C, in Casa Grande.  The telephone is (520) 836-5221, extension 204.  The author’s email address is gibsonrd@ag.arizona.edu.

The University of Arizona is an equal opportunity, affirmative action institution.  The University does not discriminate on the basis of race, color, religion, sex, national origin, age, disability, veteran status, or sexual orientation in its programs and activities.

Rick Gibson
Extension Agent, Agriculture
University of Arizona Cooperative Extension
820 E. Cottonwood Lane, Building C
Casa Grande, Arizona 85122
Voice:    (520) 836-5221
Fax:    (520) 836-1750
email:    gibsonrd@ag.arizona.edu

Mending Drip Irrigation Tubes

Ever cut through a drip irrigation line?  I have and it is not a good feeling.

There are few disconcerting, even sickening, feelings than to be shoveling merrily away in the garden and suddenly feel that distinctive “crunch” when you cut through a drip irrigation line.  When this happens you have three choices: 1) give up on gardening completely, walk away from the site of destruction, and find another hobby; 2) call someone to come fix the line, or 3) get out the tools and supplies and repair the damage.  Most of us, after having gone through the “Oh, no!  What have I just done!” stage, select number three and get it done.

Even if you are one of the lucky ones and have never sliced through a drip line, it is still a good idea to regularly make sure that all is working properly and, if not, conduct regular maintenance.  Because plants depend upon the irrigation system for life-giving water, the overall success and health of our plants is dependent upon how well the system functions.  Good maintenance is a key to garden and landscape success. Finding plugged emitters, broken lines, or clogged filters during the heat of summer is no fun, and regular maintenance during cooler weather will often prevent these mid-summer hassles.  Still, accidents happen and damage occurs.  With plastic drip irrigation systems, repairs are usually fairly simple. 

First, locate the exact site of the problem. If the tubes are underground, a sure fire test for cuts or tears in the delivery system is to look for water soaked areas on the surface of the soil.  Water escaping from a line under pressure will soak through to the soil surface and create a boggy area that is much more moist than other areas around it.  Excavate the irrigation line by digging carefully down to the tube and search for a cut or slice.  If you have an above ground system, look for geysers spraying into the air.

Once you have found the exact site, you next have to decide how best to repair it.  For simple slices or nicks, couplers are the best way to go.  To save time traveling back and forth to the store for the correct parts, it is a good idea to plan the repair job first and then assemble a parts list.  This is also the time to decide on what tools you will need.  Hunt them all up and have them ready to hand before starting the project. 

The biggest challenge to quick and easy repairs is to have the correct-sized parts on hand.  It does no good to have a three-eighths coupler to fit a half-inch line.  It just won’t work.  However, most drip tubing is of a uniform size which makes it easy to find the right parts.  It is always a good idea to double check everything before getting down on elbows and knees in the mud to do the actual repairs.

Once you have all the parts together, it is time to start the job.  At the point where the damage has occurred, use a sharp knife or small hand saw to make a straight up and down cut through the tubing.  This will make sure that all of the fittings will match evenly and seal tightly.  A cut that is uneven will leave a side with less plastic to plastic contact resulting in locations where leaks may occur.

Just about any plastic tubing can be easily repaired with slide on, or in, couplings that join the two ends of the tube in a water-tight fitting.  These couplings are available at any hardware or garden store that services drip irrigation systems. 

The barb coupling has concentric ridges on the outside and around each end of the coupling.  The barb coupling slides into the plastic tubing as far as the coupling will allow.  The barbs grasp the inside of the tube to provide the necessary tight fit.

A compression coupler is different in that it slides over the top of the plastic tubing.  Both compression and barb couplers take a little work to move them into the right position for a strong, water-tight fit.

Those who are experienced in making repairs generally agree that the compression coupler is the better way to go.  Even though they are almost double in cost over the inside-the-tube barb couplers, they seem to have a better track record of success.  This is probably due to the water pressure inside the tube.  As pressure builds, the tube expands or swells in diameter slightly.  For compression couplers, the increased pressure pushes the tube  even tighter against the coupler, and thus, creates a tighter fit.  On the other hand, the pressure tends to loosen the connection between the inside-the-tube barb couplers.

If the damage is in thicker-walled PVC pipe, slide-on PVC couplers will work for small breaks, but extensive damage may require the replacement of sections of pipe.  Remember that PVC must be glued together with an approved adhesive.

Damage to above-ground feeder lines or emitters are fairly easy to repair.  Most systems are designed to add or remove emitters easily.  Holes created for emitters or spaghetti tubing can be plugged by snapping in “goof plugs,” attachments that are designed to correct mistakes in the assembly process.

Sometimes drip system filters will become plugged with precipitated salts, algae, or sand.  Most filters can be removed and rinsed to ensure good service.  If the screen inside the filter is damaged, replace it. The filter is a critical part of the system and scrimping and “making do” can cause you many headaches down the road.

All drip irrigation systems need to be flushed out regularly to get rid of accumulated contaminants that might collect at the end of the tube.  At the end of each line, there should be an access point which can be opened to allow the water to flow freely.  Once opened, the water pressure should push out any contaminants that might be inside.

With a little know-how and some time, your labor-saving system can be back up and running just like new, that is, until you cut it again.

If you have questions, you can reach one of the Master Gardeners at the Cooperative Extension office, 820 E. Cottonwood Lane, Building C, in Casa Grande.  The telephone is (520) 836-5221, extensioin 204.  The author’s email address is gibsonrd@ag.arizona.edu.

The University of Arizona is an equal opportunity, affirmative action institution.  The University does not discriminate on the basis of race, color, religion, sex, national origin, age, disability, veteran status, or sexual orientation in its programs and activities.

Rick Gibson
Extension Agent, Agriculture
University of Arizona Cooperative Extension
820 E. Cottonwood Lane, Building C
Casa Grande, Arizona 85122
Voice:    (520) 836-5221
Fax:    (520) 836-1750
email:    gibsonrd@ag.arizona.edu

Minimizing a Heat Island Effect

We live in the Sonoran Desert.  Because of that we are accustomed to hot summer temperatures.  Have you ever noticed that the temperatures in Phoenix always seem to be several degrees higher than in the smaller communities around?  This is often referred to as the heat island effect.

The heat island effect is a natural phenomenon that causes daytime temperatures within cities to increase by up to 6 degrees F. over temperatures in rural areas at the same time of the day.  Nighttime temperature differences can be as much as 9 degrees.

Are you finding yourself a little skeptical?  Let’s look at an example.  If the daytime temperature in rural areas hits 106 degrees, which we would say is a pretty nice day for late June and July, the addition of another 6 degrees turns a tolerable day into a 112 degree scorcher.  If the rural temperatures are higher, as we know that they will be, ... well, you can do the math.

Heat islands are caused, pure and simple, by urbanized development and growth.  Roads, buildings and other hard surfaces, especially dark-colored surfaces, absorb and retain heat.  Surface temperatures fifty to seventy degrees hotter than normal soil surfaces are not uncommon.  It is the accumulation of this heat, and its subsequent release back into the atmosphere, that leads to higher ambient temperatures in urban areas.

In a 2002 article in the scientific journal Urban Ecosystems, 6: 183-203 named “Urbanization and Warming of Phoenix (Arizona, USA): Impacts, Feedbacks and Mitigation”, the authors found that at Sky Harbor Airport, urbanization has increased the nighttime minimum temperature by 5 degrees C., or 9 degrees F., and the average daily temperatures by 3.1 degrees C, or 5.6 degrees F.  Additional studies have recorded temperature increases in other cities.

High temperatures affect us in many ways.  In addition to simple heat stress to you and I, other effects, proven or implied, include increased crime rates, higher cooling bills during the summer, additional stress on landscape plants and higher insect pest activity. 

Crime rate increases in warmer weather versus cooler weather have been seen and documented in many places.  A mathematical formula has even been developed.  Plugging in the 3.1 degree C. increase in Phoenix into this formula tells us that the higher temperatures could mean an increase of an additional 25 violent crimes per 100,000 annually.  There is some controversy over whether there is a downturn in the temperature-crime relationship at very high temperatures, so this effect needs more study.  

Higher temperatures bring on a greater need for power to cool our homes, businesses and public buildings to comfortable levels.  Increasing demand generally means higher prices, and in times where the stress is severe, the imposition of a “brown-out” or even a complete short term loss of power is possible.   

In our gardens and landscapes, increased heat can affect the overall health of plants and lead to specific problems, such as water stress, sunburn and leaf tissue damage.  Insect pests, such as whiteflies, whose life cycle is temperature driven, can cause significant problems when their fast growing populations overwhelm a plant’s natural defenses.

The increased heat can also affect local food and fiber production.  Examples include the adverse effect of heat stress on dairy cows and the potential for heat injury to cotton boll production.

So, what can be done?   Houston, Texas has an interesting program called ‘Cool Houston”.  In their program, they advocate the use of cool roofs, cool paving and trees and other vegetation.  You might want to check out their website at http://www.harc.edu/harc/Projects/CoolHouston/. 

Roofs of buildings generally are completely exposed to the harsh sunlight, unless they are protected by the shade of large trees.  The use of highly reflective, lighter colored roofing materials can help reduce temperatures by reflecting sunlight back into the atmosphere instead of allowing it to heat the roof, the interior of the attic, crawl spaces and even the interior of the building.  Most roofing companies recommend this type of covering, especially for flat roofs.

Dark surfaces of streets and parking lots absorb considerable heat during the bright, sunny days and re-radiate the heat back into the atmosphere when the sunlight ends at sunset.  Light-colored pavements tend to reflect sunlight and do not heat as much as darker colored pavements.  There is a need to give these hard structure alternatives some thought.

Trees and shrubs are sure to help minimize heat gain in both public areas and in our home yards.  Not only do they shade surfaces, they also give off water vapor.  This process is known as transpiration and it cools not only the plants but surrounding areas as well.  Most of us have noticed the difference in temperature at night as we enter agricultural zones from bare desert areas.  It is the water vapor given off by plants as part of their essential life processes that cause this cooling effect.  Even most low water use plants transpire water. 

Not only do we need to plant more trees, but we can also take better care of those trees and shrubs that we already have.  Healthy thriving trees give much better shade and transpire more effectively than those that are stressed or dying.  Good management now, including the proper care of trees and shrubs, can give us huge returns later in lower cooling bills and in more comfortable living conditions. 

To finish up, let me boil this discussion down into the basics.  Urban warming affects us all.  The key effects include increased minimum daily temperatures throughout the year, a longer warm period and shorter cool period within a given day and an extended hot season. 

While some warming may be impossible to avoid as urban growth overtakes the communities of Pinal County, there are some steps that can be taken to minimize the effects.  Now is the time for all of us to get involved.

If you have questions, you can visit with one of our Master Gardeners at the Cooperative Extension office, 820 E. Cottonwood Lane, Building C, in Casa Grande.  The telephone is (520) 836-5221, extension 204.  The author’s email address is gibsonrd@ag.arizona.edu.

The University of Arizona is an equal opportunity, affirmative action institution.  The University does not discriminate on the basis of race, color, religion, sex, national origin, age, disability, veteran status, or sexual orientation in its programs and activities.

Rick Gibson
Extension Agent, Agriculture
University of Arizona Cooperative Extension
820 E. Cottonwood Lane, Building C
Casa Grande, Arizona 85122
Voice:    (520) 836-5221
Fax:    (520) 836-1750
email:    gibsonrd@ag.arizona.edu

Whiteflies in the Fall

Some people tell me that they haven’t seen any whiteflies in their gardens this year, but I can tell you from my own observations that those pesky critters, like the principle villains in a horror movie, are out there right now.

If you are new to the area and unfamiliar with the beasts, look for tiny white insects fluttering in the air during the early morning hours.  The heavy fall flights haven’t quite started yet, but there are plenty of young ones storing up energy and getting ready to do their thing.  We start looking for them as the long summer starts drawing to an end.

The sweet potato whitefly usually becomes noticeable to most people towards the end of the August or early September as they flutter around in the early mornings.  Large numbers can usually be seen through September, depending upon how long the hot weather hangs around.  White, greasy stains on the car or truck windshield are often one of the first signs of heavy whitefly populations.  These small insects eat by sucking plant juices up a tube-like mouth part. Feeding by large populations can seriously damage, stunt or destroy a large variety of garden and landscape plants. 

The sweet potato whitefly was first identified as a serious plant pest about twenty years ago.  A tropical, heat-loving insect, it seems to thrive under desert conditions and is a serious threat to many area plants.  It damages plants by removing fluids and nutrients from the plants faster than the plant can replace them.  When susceptible plants are heavily infested, it is important to water and fertilize more frequently to help offset the feeding damage.  Whiteflies also cause feeding disorders in some plants.

These insects have yellow bodies with white wings covered with a waxy powder.  Other types of whiteflies found in Arizona include the greenhouse whitefly, which thrives in greenhouses, and the ash whitefly, which is found mainly on ash and citrus trees, none of which is as serious a threat to good plant health as the sweet potato whitefly.

Sweet potato whiteflies are small insects, about the size of a pinhead, and while they do not fly as gracefully as other insects, they are adept at moving from place to place.  Their style of flight is a simple flutter that serves to suspend them in the air while they either stumble upon a new host or are blown by the wind to a hospitable spot.  Airplane pilots have reported the impact of whitefly insects on windshields as high as 1000 feet above the ground, sometimes in relatively large numbers. 

Temperature is important to these animals.  Cool weather slows its reproductive rate while warm temperatures speed it up. That is why so many are seen at the end of summer and not during the winter.  They are here in the winter, but not in numbers that can easily be seen.

These particular whiteflies feed on a number of different kinds of plants.  Their host range is fairly large, ranging from vegetables, like lettuce, melons and squash to cotton where they contaminate open bolls of lint with their excrement; a clear, sweet liquid that reduces the quality of the cotton fibers by causing them to become sticky.  They also feed on many ornamental plants. 

Plants growing in the fall, however, are the most devastated when sheer numbers of whiteflies overwhelm the defensive mechanisms of many plants and leave them weak and stunted.  There is good news, though.  If the plants can survive through the summer into periods of cooler temperatures, they will quickly recover as the populations decline.

Whiteflies begin their life as they emerge from eggs laid by adults.  The immature nymphs are the most damaging forms because of the amount of nourishment they need to mature, but all stages, including the egg, pull fluids from the plant tissue upon which they rest.

When the adult whiteflies find a suitable host, such as lantana, hibiscus, grapes, annual flowers, herbs, or vegetables, they lay their eggs on the underside of the leaves, particularly along the veins of the leaves.  The eggs hatch into “crawlers” that move around until they find a good place to feed.  Once they have settled down, they molt and become what look like tiny transparent scales.  The immature nymphs continue to feed by sucking juices from the plant.  Eventually the insects emerge as the winged adults, which fly off to new plants.

Some plants are definitely more susceptible to damage than others.  When whiteflies are numerous, they may be found resting on virtually every plant, but they are not necessarily causing damage.  To determine which plants may have a problem, examine the underside of the leaves for immature nymphs or other signs of these insects.  Although the eggs and nymphs are difficult to see with out the aid of microscope or hand lens, the underside of the leaf will have the texture of sandpaper, and probably will have tiny droplets of sticky plant sap.  Plants heavily infested with immature whiteflies may turn yellow and wilt.  Sooty molds may grow in the excrement, called honeydew, causing the plant to turn an unsightly gray or black color.

Whiteflies have been shown to carry a number of virus diseases of annual plants, but they do not seem to infect trees and shrubs.  If an annual plant becomes infected with a virus, little can be done except remove and destroy the plant.

Control requires a series of steps to suppress the populations.  A good first step is to spray regularly the underside of the leaves on susceptible plants with a strong stream of water.  This helps wash off the young immature stages and even some of the adults.  Now is a good time to start doing that because most susceptible plants are starting to show heavy immature populations.

Insecticidal soap sprays are also a good way to kill the young insects.  The soap clogs up their breathing tubes and melts away the waxy outside layers.  If it doesn’t kill them outright, they eventually die from dehydration.  There also insecticide options available.  If you choose one of these, be sure to read the label carefully because some materials cannot legally be sprayed onto edible fruits and vegetables.  Okay, let’s be real here.  It is pretty tough to control whiteflies and even a combination of these options may not give complete control.  The best we can do is to help our plants limp through to the end of the season.

Perhaps the easiest way to avoid whitefly damage is to simply not grow those plants that are most sensitive to whiteflies, or if they are annual plants, when whitefly populations are greatest.  For example, delay planting fall vegetable gardens and annual flower beds until the second week in October, or until the whitefly numbers have dropped off.

While we do not have a really good method to control these garden and landscape pests, we can take hope that the cooler weather that is coming will slow them down once again.

If you have questions, you can reach one of the Master Gardeners at the Cooperative Extension office, 820 E. Cottonwood Lane, Building C, in Casa Grande.  The telephone is (520) 836-5221, extension 204.  The author’s email address is gibsonrd@ag.arizona.edu.

The University of Arizona is an equal opportunity, affirmative action institution.  The University does not discriminate on the basis of race, color, religion, sex, national origin, age, disability, veteran status, or sexual orientation in its programs and activities.

Rick Gibson
Extension Agent, Agriculture
University of Arizona Cooperative Extension
820 E. Cottonwood Lane, Building C
Casa Grande, Arizona 85122
Voice:    (520) 836-5221
Fax:    (520) 836-1750
email:    gibsonrd@ag.arizona.edu

Plants Provide Many Benefits In Our Lives

In a hurry up world where life seems to constantly accelerate and the day-to-day challenges appear to bring ever more stress, plants can impart a sense of needed stability and well-being in our lives.

Not surprisingly, recent scientific studies indicate a strong relationship between healthy people and exposure to plants, both indoor and out.  Here are some examples taken from a series of articles published in the January-March 2000 edition of  “HortTechnology”, a quarterly journal for horticultural professionals.

The first example comes from one of the earliest studies looking at the beneficial effects of plants.  Patients having a room with a view of trees rather than a view of a brick wall spent almost a day less in the hospital, used fewer doses of strong pain relievers, and received fewer negative comments from hospital staff on their charts.  The study instantly attracted the attention of both the medical community and horticultural researchers. 

In another study, people in an experiment viewed slides of nature scenes with water and vegetation, slides of nature scenes with only vegetation or slides of urban scenes without vegetation.  When people viewed either of the nature scenes, they exhibited higher alpha brain wave amplitudes than when viewing urban scenes. 

Now stay with me here.  Higher alpha brain wave amplitudes are generally associated with lower levels of physiological arousal and higher levels of attentive relaxation.  In other words, they were judged to be under less stress.  That is a good thing.  The subjects also reported that the nature slides held their attention better than the urban slides, even though all of the slides were judged to have similar informational content.
           
One study focusing on college students showed that those performing tasks that required deep mental concentration performed significantly better on some tests when they enjoyed a window room that opened out onto a nature scene than those who had views of scenes dominated by buildings and sidewalks.  Nature scenes seemed to enhance mental attention and reduce fatigue.

A 1996 study asked apartment complex residents about domestic violence.  Respondents lived in public housing and could not choose their apartments.  Some were assigned to live in complexes surrounded by trees, while others were assigned to buildings without green surroundings.  When asked if they had engaged in violence during the past year, 22% of the women interviewed from the apartments without trees said “yes” while only 13% of the women in the apartments surrounded by trees said “yes”.  When asked if they had hit their children in the past year, 14% from the non-green apartments said “yes”, while only 3% living in apartments near trees said “yes”.  

The list of studies goes on and on, here in the U.S., and around the world.  The evidence is quite clear.  Scenes associated with plants can reduce stress, speed healing, enhance workplace productivity and improve the human outlook on life.  

These results have not gone unnoticed.  Around the world, plants are showing up more and more inside public buildings, in malls and in hospitals and long term care centers.  School gardens are being planted and cared for.  Adults working in the court systems assign juvenile offenders to work in community gardens.  Horticultural therapy has become a viable tool in the medical field. 

These real benefits, however, are sometimes masked, covered up, if you will, by the very challenges of life that make our involvement with plants so essential.  The bottom line is that we are becoming too busy to garden, to care for house plants and to plant trees and shrubs. 

If we do install landscapes, we often give in to the temptation to make them so labor-free that we do not find the need to interact with them in any way other than in the most brief of encounters.  This may be helpful in our busy worlds, but it is expensive in terms of the very real benefits that could possibly be ours.

So, what can you and I do?  There are several ways to enhance our interaction with plants and to improve the surroundings in which we live.

First, bring plants indoors.  Look around the interior living space and search for locations where an indoor plant might fit.  Identify  locations where light, humidity, and temperature conditions fit the needs of the plant.   For example, do not place a boston fern in an area where the cooler or heater vents would blow on the plant and dry it out.  Ferns like moist, humid areas such as in the shower or bath. 

Group indoor plants into natural appearing arrangements that give a sense of the outdoors from which they came.  Such arrangements help create a peaceful, natural feeling similar to that experienced in native environments.

Second, search for ways to make outdoor landscapes user friendly.  Arrange and install outdoor landscapes with the intent that they will encourage human interaction.  Select plants that fit the specific needs of the landscape and of the people that will use it.  Let the landscape be an extension of the home so that it will be an easy and natural step to exit the home and immerse oneself in the outdoors.  A well designed and maintained landscape will entice people indoors to move outside.

Consider placing benches or chairs in strategic locations that invite a passerby to linger and enjoy the setting.  This may be tucked away between trees or behind shrubs away from busy traffic areas, or it may simply be next to favorite flowering shrubs or garden areas.  Such locations encourage introspection and relaxation from busy schedules.

Third, notice the use of plants and natural environments in public places and recognize them for what they bring to those who visit those areas.  Many malls, for example, spend considerable resources to bring the natural environment inside for a peaceful, if not restful, shopping experience.  Encourage businesses and other establishments that you frequent to consider installing plants into their decor.  Tell them about the potential benefits that could come both to them and their customers from the practice.

Fourth, become active in neighborhood and community beautification committees, school garden projects and community garden efforts and encourage the proper use of landscapes and indoor plants in all areas.  Volunteer time not only lifts those served, but also reaps benefits to those serving.

Finally, become informed about plants and the potential benefits that come from human interaction with plants.  Know how to properly select, install and care for indoor and outdoor plants in our harsh, desert environment. 

Healthy plants in our living environment can help all of us accrue actual emotional, physical and psychological benefits each and every day.  The bottom line is, plants help us live better lives.

If you have questions, you can reach one of the Master Gardeners at the Cooperative Extension office, 820 E. Cottonwood Lane, Building C, in Casa Grande.  The telephone is (520) 836-5221.  The author’s email address is gibsonrd@ag.arizona.edu.

The University of Arizona is an equal opportunity, affirmative action institution.  The University does not discriminate on the basis of race, color, religion, sex, national origin, age, disability, veteran status, or sexual orientation in its programs and activities.

Rick Gibson
Extension Agent, Agriculture
University of Arizona Cooperative Extension
820 E. Cottonwood Lane, Building C
Casa Grande, Arizona 85122
Voice:    (520) 836-5221
Fax:    (520) 836-1750
email:    gibsonrd@ag.arizona.edu

The Tecoma Leaf-Tier

Last year was the first year that we saw the Tecoma leaf-tier here in Central Arizona.  It came as quite a shock to us at that time because samples started coming in from all over the county, all at the same time.  Not only that, they were also being seen in Phoenix and Tucson.

We were able to identify the insect and learn about its biology.  We also were able to work out management recommendations.  We wondered if the insect would be able to become established in our climate and decided to take a wait and see approach.  That question has now been answered.  They are still here and doing their thing.  You guessed it.  Samples are coming in as we speak.  If you are growing one of the Tecoma species, let me provide a little background information on this insect pest, what to watch for and what to do if you find the feeding damage.

The insect pest is commonly know as the leaf-tier.  Antigastra catalaunalis is the scientific name.  It is a member of the pyralid family. 

It is important to know that the insect feeds primarily on yellow and orange bells, Genus Tecoma. 
Are you familiar with the tecomas?   “Landscape Plants for Dry Regions,” by Warren Jones and Charles Sacamano, recommends four separate species of Tecoma for our area.  Tecoma alata is commonly known as orange bells or orange-flowered tecoma.  The Argentine tecoma is Tecoma garrocha.  Tecoma stans angustata is the narrow-leaf yellow bells, sometimes called the narrow-leaf trumpet bush; and the fourth is Tecoma stans stans, or the Mexican yellow bells.  All are shrub-like plants.

The tecomas are fairly common in area landscapes.  We like them because they are drought resistant; produce large, showy flowers and, until last year, were pretty much problem free.

The samples are all the same. Instead of a healthy green, many of the leaves are a pale tan where the leaf tissue has been eaten down to a thin, almost transparent layer.  On some plants, the damage can be fairly heavy; in some cases as many as one-half of the leaves showing symptoms.  Some leaves are folded over and sealed with webbing.  No, not spider webs.  The webbing is more dense, like a protective covering that some moth larvae use to protect themselves.  The webbing is speckled with small, black fecal droppings.  In the business, the name we use to describe these droppings is frass. 

The webbing and the frass are a dead giveaway that the insect is a moth and the treatment of first choice for these caterpillars is pretty straight forward.  In almost all cases, we recommend the use of an environmentally safe and organically approved bacteria-based insecticide called Bacillus thuringiensis, or “Bt” for short.

Bt is the active ingredient of a pesticide approved not only by the Environmental Protection Agency but also by organic standards for moth larvae feeding on landscape, ornamental and vegetable plants.  It causes a bacterial disease in the larval stage of the insect’s development.  Once they pick up the disease organism, and it begins to work, the animals stop feeding, get sick and die.  It is generally pretty effective and altogether safe for other animals and plants, including humans.  We use it in many situations and, like I said, it is usually a good choice for moth larvae pests.

If you find symptoms on Tecoma, first determine the amount of damage that you are seeing.  If it is only one or two leaves, you may want to hold off on taking action.  I recommend that you take a "wait and see" attitude. Plants can take a lot of feeding damage without significant harm.  If the symptoms of damage continue to get worse and you need to use a  chemical control, use a Bt subspecies kurstaki product at the maximum labeled rate. The caterpillar's habit of protecting itself with webbing and folded leaves means that contact insecticides, insecticides that you spray onto the insects themselves, will probably not work.

If you have questions, you can reach one of the Master Gardeners at the Cooperative Extension office, 820 E. Cottonwood Lane, Building C, in Casa Grande.  The telephone is (520) 836-5221, extension 204.  The author’s email address is gibsonrd@ag.arizona.edu.

The University of Arizona is an equal opportunity, affirmative action institution.  The University does not discriminate on the basis of race, color, religion, sex, national origin, age, disability, veteran status, or sexual orientation in its programs and activities.

Rick Gibson
Extension Agent, Agriculture
University of Arizona Cooperative Extension
820 E. Cottonwood Lane, Building C
Casa Grande, Arizona 85122
Voice:    (520) 836-5221
Fax:    (520) 836-1750
email:    gibsonrd@ag.arizona.edu

Proper Planting and Irrigation Can Prevent Wind Throw of Trees

The past few weeks have brought the expected monsoon storms with strong winds and thick, blowing dust.  Sadly, there have been many trees that have been damaged or lost because of wind throw. 

Wind throw is a term that is used to describe the toppling of trees, large cacti, and some thick- branched shrubs by heavy winds.  It usually occurs when top heavy, poorly rooted, thick-canopied plants are pushed by strong winds, such as those found during our severe desert storms. Toppled trees fall over onto their sides leaving their roots upright and exposed to the air. 

The good news is that well rooted trees should be able to withstand even the most vicious of storms.  Wind damage is not unavoidable.  If sound horticultural practices are applied, most trees will be safe from even the most devastating of winds.  Proper planting and irrigating of trees and shrubs are the best protection against wind throw.

Most trees, especially the desert-adapted trees, are best planted following the instructions in the University of Arizona Cooperative Extension Bulletin AZ 1022 entitled “Planting Guidelines: Container Trees and Shrubs”.   Proper planting requires the excavation of a planting area three to five times the width of the root ball or box, but no deeper than the depth of the container.  The old adage of digging a hole “four feet by four feet by four feet” is no longer held in good favor because it tends to constrict the growth of roots into that specific, narrow area.  Large trees with small root systems are particularly susceptible to wind throw.

A caliche layer or other type of hard soil layer underneath the tree can also restrict the development of a strong root system.  If either of these are present, it is a good idea to drill or dig a drainage chimney to one side of the hole, so that excess water and dissolved salts can drain out of the root zone.  Make sure that the chimney is to one side of the root ball, not directly underneath.  With desert species, amending the soil that will go back into the hole is not recommended.

Timely and effective irrigation is another key to the development of a strong, dispersed root system.  Irrigation systems that are designed, installed and managed to provide the long and short-term water demands of the plant will help ensure vigorous root exploration and growth.

Please remember that roots only grow into moist, not dry, soils.  This is one of the basic rules of plant growth and we violate it only at the risk of causing landscape disappointments later on.   Irrigation wells or drip system emitters must reach out to the edge of the tree canopy in order to encourage the growth of a root system capable of withstanding the strong winds of desert monsoons.  Trees that receive water from small water basins next to the trunk of the tree will have small root systems that cannot provide good support during high winds.

Sometimes we want to cut back on irrigation expense.  If there is a large tree present, it will have developed an extensive root system wherever irrigation water has been applied.  If water is suddenly cut off to the tree under the guise of cutting back on the water bill, there is a good chance that the root system will also begin to die back, thus weakening the tree’s support.  As support weakens, the tree will be more susceptible to wind throw. 

A drip irrigation system is a good way to cut back on the water bill and still protect the health of trees and shrubs.  Installation of twelve drip emitters in an “X” pattern underneath trees is the best way to ensure good distribution of water with a mechanical irrigation system.  The first three emitters should be near the trunk with the last two in each arm of the “X” three to four feet out from the previous emitter.  This arrangement will allow root growth out to about twelve feet in all directions.  The resulting root system will be well dispersed and able to balance the top growth of the tree.  The more extensive the root system, the less likely a tree will blow over in the wind.

Root growth occurs throughout the year, not just during the active growing periods of the above ground parts.  With appropriate watering in the summer months, roots of a newly planted tree can grow beyond the leaf canopy in thirty to sixty days.  These newly planted trees and shrubs need the emitters placed near the trunk to help settle and compact the soil above the fresh root ball, but as the tree matures, however, emitters near the trunk should be closed in favor of emitters near the outer edge of the expanding leaf canopy.  Additional emitters might be needed if the tree canopy continues to expand past the last emitters on the line.

If stakes are used with young trees, they should not be left indefinitely.  Good root growth will encourage good trunk growth and allow the resulting tree able to stand on its own within a short period of time.  If a tree is dependent upon stakes and wires to hold itself up, there probably is a problem with the root system.

Tree form or structure also plays a role in wind throw.  Properly selected and shaped, low-branching, upright trees will have a natural strength that will stand up to strong winds. Some pruning might be helpful to lighten the wind resistance of the canopy but heavy pruning may do more damage than good.  A rule of thumb to follow when pruning trees and shrubs, especially the desert adapted mesquites, is to lightly and frequently remove about 20 percent of wood at any one time.  Most of the wood that is removed would come from the outer 20 percent of the canopy and promote natural branch tapering while opening up the canopy to light and wind.  This process also helps retain the natural beauty and appearance of the tree.

Wind throw is all too common a problem for trees and some shrubs during the high wind episodes of our monsoon storms, but, good planning and care of susceptible plants can help avoid the frustration of having to replant expensive trees every three to five years.  In Arizona, every tree is worth its weight in gold.

If you have questions, you can reach one of the Master Gardeners at the Cooperative Extension office, 820 E. Cottonwood Lane, Building C, in Casa Grande.  The telephone is (520) 836-5221.

The University of Arizona is an equal opportunity, affirmative action institution.  The University does not discriminate on the basis of race, color, religion, sex, national origin, age, disability, veteran status, or sexual orientation in its programs and activities.

Rick Gibson
Extension Agent, Agriculture
University of Arizona Cooperative Extension
820 E. Cottonwood Lane, Building C
Casa Grande, Arizona 85122
Voice:    (520) 836-5221, 227
Fax:    (520) 836-1750
email:    gibsonrd@ag.arizona.edu

Benefits of Keeping a Garden Journal

Are you keeping your garden journal up-to-date?

A garden journal is a written document kept update through the growing season to record and keep track of important garden information that you want to remember and possibly reuse in the future.  It is also an excellent way to enjoy the garden year round, and to bring to quick recall favorite garden experiences.  Many find garden journals great leisure reading.  Perhaps the greatest benefit is that they can help us correctly manage and care for our gardens and landscapes.

A garden journal can take many forms.  It can be simply a brief listing of specific plants and their performance during the growing season, or it can be an in depth history of the lives of people enjoying the simple pleasures of gardening.  Filled with photos and drawings, and notes of feelings and insights, a journal can be a book of fond memories just as much as it is a record of life emerging from the soil.  

A journal takes on the personality of the author and its benefits are as numerous and as varied as the reasons that it is kept.  If you think a garden journal is for you, here are a few ideas to get you started.

First, think of your garden journal as a tool, a very important tool to help you maintain a productive garden.  If you are an avid gardener, you may have so many plants that it becomes easy to forget when you last fertilized your rose or watered your citrus tree.  A journal will help you remember what task you performed for each plant, and when.  Many dead or dying trees and shrubs would probably be alive and well today if we could have just remembered when we last gave them water.

The content of the garden journal should include the important basic information of planting dates and the dates the plants emerged from the soil.  The time between planting and germination is always a difficult time for young plants and is affected by temperature, rainfall and light intensity.  Each year many of us try to get an earlier start in our gardens to avoid the problems of heat and insects later on.  By recording planting and germination dates we can keep track of how well our plants do in the early season.  That information will tell us whether we can squeeze the calendar a little more, or whether we should wait for warmer temperatures. 

The same goes for harvest.  We should record not only how well the plants do during the growing season, but we should also note the quality and quantity of the harvest at the end of the season.  This information, recorded in the journal, will be available for you to ponder the next time you select a planting date.

If you are into flowers, blooming periods are important information to collect.  Many are trying to ensure a colorful garden for a party or family gathering.  Information related to peak blooming times, tied to the planting calendar, will help you remember year to year what worked best.

Many of us like to experiment with different varieties.  As we get older, our “forgetters” seem to get better.  Soon, if we do not write it down, we can’t remember the varieties we have tried in the past.  Then, we either begin to duplicate ourselves, or we forget how well a particular variety performed in the garden.  A journal will help capture this important information.

Do not forget to record the costs of plants and supplies.  How better way to build a good budget for that next garden than by keeping track of the actual costs of keeping the garden productive and healthy? 

In the interest of good plant health, it is important to remember what plants went into which part of the garden in a given season.  Crop rotation has been an important cultural tool since the early years of agriculture.  Because rotation helps prevent the build up of disease pathogens and insects, recording plant locations each year will help us decide where specific plants should be placed in the garden. 

Into the journal should also go details of all garden tasks that you do.  When you perform a specific operation like feeding, watering, spraying and pruning, write it down for future reference. 

Styles of record-keeping can range from nearly clinical listings of plant names and bloom dates to sentimental narratives chronicling both facts and feelings.  The contents of garden notebooks and journals could vary from harvest recipes to weather data and from equipment warranties to vegetable taste-test results. 

A three-ring binder with a washable cover and an inside pocket to hold pens and pencils is a great choice for recording garden information.  The ring binder gives flexibility to add pages as needed and to slip in clippings and other useful information.

Some people divide the notebooks by month using plastic-covered index tabs on dividers.  Behind each divider they place a page from a store-bought calendar.  You can either fill in the daily calendar squares with ‘to do’ lists gleaned from magazines and Cooperative Extension garden columns, or you can keep track of the day’s achievements, such as when a particular garden bed or tree was watered.

While this much information may be sufficient for some, others may want to follow the calendar leaves with lined paper for making detailed notes on garden activities, and impressions, such as successful plant combinations, weather patterns, including their effect on the plants, and reminders to move plants or allow more time for certain garden tasks. 

Another useful addition to the notebook is a reference section organized alphabetically to keep track of books and tools.  In clear plastic inserts, you may want to slip seed packets, plant tags, articles, and instructions.

You may decide that you want to design your own data forms.  You might, for example, assemble a form that records a plant’s common and botanical names, characteristics and use, size, bloom season, cultural requirements and pests and diseases.  It all depends upon your needs and interests.

As you personalize your journal, you may want to write in it daily or you may decide to write only when important information presents itself.  For example, you may decide to walk through your garden on the last day of the month and make notes that will be important to you.

When it comes time to begin a new year, simply add extra pages to the monthly sections.  If you are more ambitious, you can file each month’s entries in a separate notebook or in a file cabinet file labeled by month.

Keeping a good garden journal through the months and the years will, at the very least, help you make sound decisions in the garden.  If you have kept track of family events, such as garden parties, a wedding, new garden renovations and new pets, you will have at your fingertips a set of memories that will last a lifetime.

If you have questions, you can reach one of the Master Gardeners at the Cooperative Extension office, 820 E. Cottonwood Lane, Building C, in Casa Grande.  The telephone is (520) 836-5221, 204.  The author’s email address is gibsonrd@ag.arizona.edu.

The University of Arizona is an equal opportunity, affirmative action institution.  The University does not discriminate on the basis of race, color, religion, sex, national origin, age, disability, veteran status, or sexual orientation in its programs and activities.

Rick Gibson
Extension Agent, Agriculture
University of Arizona Cooperative Extension
820 E. Cottonwood Lane, Building C
Casa Grande, Arizona 85122
Voice:    (520) 836-5221
Fax:    (520) 836-1750
email:    gibsonrd@ag.arizona.edu

Eco-Friendly Gardening

More and more people are becoming interesting in growing at least some of their own food in an earth-friendly manner.  For many, maybe even most, that means organic gardening.  It is important to know, however, that organic production is not the only system that is eco-friendly.  Let’s take a look at some of the others. 

Organic gardening is not new.  The term “organic” has become quite popular as more and more shelf space in the supermarket is dedicated to food grown through organic processes.  To be sold as organic, a product must be certified by an outside oversight group, usually a private, non-profit organization.  Only after rigorous review can a product receive the USDA organic label.

It is well known that organic production requires fruits and vegetables to be grown without synthetic pesticides or fertilizers.  In addition, organic gardeners strive to replenish nitrogen and other key elements through processes that mimic nature.  The use of cover crops, green manures, and composted animal manures are good examples. 

Organic gardening also strives to build soil resources, like tilth and friability, by adding organic matter to the soil.  Experienced organic gardeners feel that the best way to feed a plant is to feed the soil itself.   The use of beneficial insects and crop rotations help manage weeds, insects, and diseases.

Other eco-friendly production systems accept the basic assumptions of organic production, but are different in that they add other ideas to the production system.  Three of the most prevalent include biodynamic, biointensive, and permaculture gardening. 

A biointensive system focuses on producing maximum yields from a minimum area of land.  At the same time it strives to simultaneously improve the soil. The goal of the method is long term sustainability on a closed system basis. The system has also been used successfully on small scale commercial farms. 

The biointensive method is rooted deep in human history.  Elements of biointensive farming can be found in the ancient Mayan and Aztec farming systems of Central America and the Chinese systems in Asia.  The Greeks in the Mediterranean area and early feudal Europe also practiced biointensive farming.  In each case, these systems supported large and growing populations.  It is important to note that these civilizations flourished when the stability of the soil was maintained but declined when for one reason or another the soil became impoverished.

Key elements of some biointensive systems include double digging, companion planting, and intensive planting.  The soil is often spaded or tilled deeply by loosening the upper layer of soil to the depth of a spade and then setting it aside.  The lower level of soil is then tilled or spaded and the original soil either replaced or, more commonly, spaded into from the next slice of ground to be tilled.  The soil is often heaped up into raised beds that are never walked on and are carefully maintained with compost and other natural materials.

Companion planting places multiple crops at the same time in the same place.  The ancient American technique of planting corn, beans, and squash intermingled into the same bed is a good example. These crops helped each other by providing support and nutrients for each other. 

A form of companion planting also occurs as crops are rotated from season to season.  In this system, a different crop is planted in a given location each growing season.  Three field crop rotation became a staple of feudal Europe agriculture.  We still use crop rotation today in our mainstay agricultural systems.

Intensive planting places crops in close proximity together either in rows or beds, or in clearly defined areas, such as in the waffle gardens of the Pueblo tribes of northern Arizona and New Mexico.  We often practice intensive planting today when we use the square foot garden technique.

Biodynamic gardening was developed in Germany by Rudolf Steiner.  It emphasizes the holistic growing system and maximizes the interrelationship of the soil, plants, and animals as a closed, self-nourishing system.  It values manures and composts as sources of nitrogen and other nutrients and, like organic gardening, excludes the use of artificial fertilizers and other chemicals.  Among its techniques are the use of fermented herbal and mineral preparations as compost additives.  Those who practice biodynamic gardening feel that they are producing food that augurs well with the production cycles of the earth itself.

Permaculture gardening is a system that was originally created in Australia by David Mollison and David Holmgren.  The word permaculture is a hybrid of two common words, permanent and agriculture.  The systems strives to integrate the use of plants, soil, climate, and animals into a unified whole where each supports the development of a system that resembles and mimics natural ecosystems.

Today, there is currently much interest in eating foods and wearing clothes that have been grown and processed in an earth-friendly manner.  Food safety, reducing the carbon footprint, and protecting the environment are just a few of the goals that have become important to us all.  We all recognize that the earth is the home in which we live our lives.  Sustainable living is the practice of living in harmony with the natural processes of the earth so that we can enjoy a healthy lifestyle and, at the same time, preserve our planet as best we can for future generations. 

There are many gardening systems that help lend sustainability to our life styles.  Many of these systems are becoming more and more popular as people strive to become more earth-friendly.  These techniques are equally at home in food systems as small as container gardens as well as in large farming operations.  As we begin to appreciate the wide variety of options available to help us choose and select the appropriate gardening system for us, we begin to appreciate the diversity and the resilience of nature itself. 

No matter what production systems you decide to use, I feel that it is important in today’s economic climate for everyone to know how to produce at least part of their food for themselves.  No matter how you choose to manage your garden, the end result should always be the same: fresh, wholesome food for our tables!

If you have questions, you can reach our Cooperative Extension office at 820 E. Cottonwood Lane in Casa Grande.  The telephone is (520) 836-5221, extension 204.  The author’s email address is gibsonrd@ag.arizona.edu.

The University of Arizona is an equal opportunity, affirmative action institution.  The University does not discriminate on the basis of race, color, religion, sex, national origin, age, disability, veteran status, or sexual orientation in its programs and activities.

Rick Gibson
Extension Agent, Agriculture
University of Arizona Cooperative Extension
820 E. Cottonwood Lane, Building C
Casa Grande, Arizona 85122
Voice:    (520) 836-5221
Fax:    (520) 836-1750
email:    gibsonrd@ag.arizona.edu

Jujube - The Less Well known Fruit

Amid questions about citrus, peaches and apricots, occasionally I get asked about a lesser known, but equally useful fruit: the Chinese date or jujube.

Ziziphus jujuba is the scientific name of this wonderful tree, but most people simply call it by its common name, the jujube.  A member of the buckthorn family, it brings an interesting shape, deep green leaves and tasty fruit to a landscape. It is widely grown in hot, dry climates around the world.

The jujube makes an excellent landscape plant.  It provides shade and has a canopy of leaves thick enough to make a good screen.  It produces lush fruit that can be eaten fresh, dried like a date or candied.  If you are into wood carving, you will just love the opportunities the wood provides.  The wood from the jujube is reddish, close-grained, fine-textured, hard, tough, durable and polishes well.  The wood can also be used to make furniture and other useful items.   For the less artistically inclined, it makes great charcoal. 

The jujube tree mixes well with lawns, shrubs and bedding plants but it strikes an especially attractive silhouette when planted all by itself.  Over time it develops a graceful, gnarled shape that gives it character and individuality. 

The tree grows at a slow to moderate rate until it reaches a mature size of fifteen to twenty feet tall and about ten to fifteen feet wide.  These dimensions make this tree a little smaller than other trees commonly available for planting in local landscapes.  Thus, the jujube is an ideal candidate for planting in smaller yards. 

The tree is best identified from the structure of the leaves.  Each glossy, bright green leaf has three prominent veins that run lengthwise along the leaf.  Most leaves are about one to two inches long.  In the fall, these same leaves turn a bright yellow color in anticipation of the winter season. 

The flowers of the jujube appear in late spring and early summer.  The many clusters of small, yellowish flowers produce the fruit that will ripen in the fall.  The fruit is harvested for eating fresh off the tree when it begins to turn from yellow-green to reddish brown.  The fruit will have a crisp texture and taste like a sweet apple.  Once the fruit reaches the stage where it is completely brown and mushy, it is better for drying.

The fruit from seedling trees are generally smaller than the regular fruiting varieties.  What are seedling trees, you ask?  Seedling trees are trees that are still on their own roots.  It is quite common in horticulture circles to graft fruit varieties, like peaches, apples and citrus, onto the trunk and roots of a different variety.  This management step usually yields larger fruit and a more vigorous tree. 

In the jujube, seedling fruit are usually about one-half to one inch long.  Fruiting varieties that are grafted usually produce fruit from one and one-half inch to two inches long.  So, if you choose to plant a jujube from seed, just remember that you may get smaller fruit.  The two most common cultivated varieties are ‘Lang’ with one and one-half to two-inch, oblong fruit and ‘Li” which produces two-inch, round fruit.  Both varieties produce better if both are planted next to each other for cross pollination, but ‘Li” will produce some fruit if planted alone.

The jujube tree has roots that penetrate deep into the soil.  Because of this, it can access water that is normally unavailable to other, more shallow-rooted plants.  When we irrigate the jujube tree, it is best to let the water run slowly over the ground so that it can fill the entire root zone.  The tree will, however, tolerate drought and the hot, dry environment of the desert.   It grows better in well-drained, fertile soils than it does in shallow, hard soils, but it does just fine in our salty, alkaline soils.  

Unlike many of our frost sensitive fruit trees, like citrus, the jujube is rarely bothered by the cold weather found here in our warm deserts.   Because the plant loses its leaves during the winter and flowers relatively late in the spring, frost doesn’t bother it.  However, in higher elevations, the tree will not produce much fruit where the summer growing season is short.

The jujube tree needs only a minimal amount of fertilizer each year to be happy.  I would give it no more than one pound of actual nitrogen each year.  If you use ammonium sulfate, 21-0-0, the year’s total would come out to only five pounds of fertilizer for the entire year.  This total should not be applied in anything less than three applications during the year.  A good approach would be to apply one-third of the fertilizer in each of the months of February, May and August.  Sprinkle the fertilizer onto the surface of the soil and then let the irrigation water slowly trickle onto the surface of the soil until it wets the entire area beneath the canopy of the tree.  The water will move the nitrogen into the soil profile.  

One drawback of the jujube is its tendency to produce sucker growth from the roots.  These individual sprouts of little trees will eventually play havoc with lawn mover blades when they begin to be thick enough to cause problems.  The tree is also quite susceptible to cotton root rot, otherwise known sometimes as Texas root rot.  The sucker growth can be kept trimmed, of course, but there really is nothing to be done if root rot organisms are present in the soil.  Root rot kills quickly and silently. 

It is not necessary to do a lot of pruning to maintain the tree.  The best time to prune is in winter during the months of late December, January and early February while the tree is dormant, that is, when the leaves are off the tree.  Other than the need to cut out the occasional rubbing branch, to slightly shape the tree, to encourage the weeping habit or to reduce size, very little pruning is actually needed.

If you haven’t guessed by now, I really think the jujube is a good fit for desert landscapes.  Yes it has a few spines, but the shade, desert hardiness and fruit make up for that and the other few problems inherent to the jujube.

If you have questions, you can reach one of the Master Gardeners at the Cooperative Extension office, 820 E. Cottonwood Lane, Building C, in Casa Grande.  The telephone is (520) 836-5221, extension 204.  The author’s email address is gibsonrd@ag.arizona.edu.

The University of Arizona is an equal opportunity, affirmative action institution.  The University does not discriminate on the basis of race, color, religion, sex, national origin, age, disability, veteran status, or sexual orientation in its programs and activities.

Rick Gibson
Extension Agent, Agriculture
University of Arizona Cooperative Extension
820 E. Cottonwood Lane, Building C
Casa Grande, Arizona 85122
Voice:    (520) 836-5221
Fax:    (520) 836-1750
email:    gibsonrd@ag.arizona.edu

When to Remove Landscape Trees

Sometimes, when a tree is diseased or damaged, there really is no other choice but to take it out, but for those who appreciate the many benefits of trees, deciding to remove can be one of the most difficult, even agonizing, landscaping decisions that they ever have to make.

It is well known that trees add value to any property.  That, coupled with their overall beauty and graceful attractiveness, makes it easy to understand why we become so attached to our trees.  Who has not enjoyed the shade of a friendly, well-located tree on a hot summer day?

Most of the time, damaged or even diseased trees can be nurtured along and brought back to health.  Good irrigation and fertility practices often enough will stimulate new, healthy growth that will allow the tree to overcome most problems.

Sometimes, however, good care is not enough.  A tree may be overly damaged from a storm or ravaged by disease.  It may be growing in a place where it can cause damage to a home or commercial building.  It may be sitting underneath a power line or interfering with the delivery of utilities.  In these situations arise, something drastic needs to be done.

It can be difficult, even in the best of situations, to know when to nurture and when to remove a tree.  However, there are ways to approach these types of decisions, and one of the best is that used by trained tree professionals.  In making a decision to keep or remove a tree, most arborists cooly consider two offsetting factors.  These factors help them put the problem into perspective and reach a final conclusion.

The first factor is the value of the target.  The second is  the potential for plant failure. 

The value of the target, in simple terms, is what, or who could be damaged or hurt by the failure of the tree.  Professional arborists look first at the value of any structure or possession and how the loss of that value may affect a specific landscape.  Having done that, they also look at the tree itself to determine if there is eminent danger of a branch breaking and falling, or if there is any reason the tree might be weak enough to completely fail in a heavy wind.  Armed with this information, most decisions become quite easy.

The single most important reason for removing a tree is, quite simply, safety.  Safety for the people closest to the tree, safety for the general public and safety for buildings or automobiles.   If there is any chance that people might be hurt from a dangerous tree, in today’s world of liability, removal is probably the best choice.

There are good examples of how safety can play a big role in landscape decisions.  Large, sick or declining trees growing near buildings, parks where children play or in planters next to high traffic areas in town often create a risk that far outweighs the benefits of those trees.

In other situations, a tree may be perfectly fine; that is, not damaged or diseased in any way.  Nevertheless, the same type of thinking has to apply.  If there is danger that a high value loss, injury or death could occur, the tree should come out.  Healthy trees under power lines, saguaros growing under the eaves of a home and trees in a position where roots could heave up a sidewalk or damage structures are good examples. 

Stated a little differently, if a dangerous tree sits over a driveway or sidewalk, overhangs the roof of a house or shelters the outdoor toys of a children’s play area, it is really an easy choice to make.  They should come out as soon as possible. 

On the other hand, if the tree is in a spot where little or no damage could occur, it is probably alright to let it remain for as long as the tree can survive.  A tree in a relatively unfrequented area may have a low hazard rating and can probably be left untouched.

Once a tree is determined to be dangerous, however, there still may be other choices besides removal.  The addition of bolts and guy wires may simply be all that is needed to solve the problem.  This process is slow and often expensive, but in some cases, it can actually save a tree. 
Sometimes simple pruning to lighten the load on a tree trunk may be all that is needed to correct a problem. This works best on younger trees where selective pruning can force growth back into vacant areas and save the life of the tree.  Older trees are generally not in an active growth phase and may not be able to respond with new growth quickly enough to fill unsightly gaps in the tree canopy or prevent possible sunburn damage to the tree. 

Unfortunately, in some cases, the dangers of leaving a tree or branch in position outweigh the potential benefits that the tree provides.  Whether this is caused by a high potential for failure in a busy location, or a limb in a bad position, there really is no other recourse.  In these cases, it is time to take it out. 

If the decision is made to remove a tree, make sure that it is done correctly.  Because trees needing removal are often dangerous, it is generally well worth the money to pay a certified professional who is trained and experienced to do the job.  Many people each year are injured or killed by following improper procedures while removing large, dangerous trees.

Mature trees represent a large investment of time, fertilizer, water and tender loving care over many years in order for them to reach mature heights.  When they do not do well, we are rightfully concerned.   The decision to remove a tree is often difficult, but in the interest of safety and common sense, sometimes they just have to come out.

If you have questions, you can reach one of our Master Gardeners at the Cooperative Extension office, 820 E. Cottonwood Lane, Building C, in Casa Grande.  The telephone is (520) 836-5221, extension 204.  The author’s email address is gibsonrd@ag.arizona.edu.

The University of Arizona is an equal opportunity, affirmative action institution.  The University does not discriminate on the basis of race, color, religion, sex, national origin, age, disability, veteran status, or sexual orientation in its programs and activities.

Rick Gibson
Extension Agent, Agriculture
University of Arizona Cooperative Extension
820 E. Cottonwood Lane, Building C
Casa Grande, Arizona 85122
Voice:    (520) 836-5221
Fax:    (520) 836-1750
email:    gibsonrd@ag.arizona.edu