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Saturday, August 18, 2012

Fruitless Olive Tree Has Fruit!

Olive flowers
Q. I read a small article on line that you wrote about "Fruitless" olive trees. We just had two new 36" box "Fruitless" olive trees planted in our front yard.  We noticed about a dozen green olives growing at the top areas of the trees.

Almond Tree 8 Yrs Old Bearing No Nuts


Q. We have two almond trees and since they produce nuts we assume that one is male and the other one female, although we do not know which is which. However, one tree bears almost no nuts. I just checked and could find only two nuts on the entire tree. The other tree is loaded with nuts. The two trees were planted at the same time, eight or ten years ago. Can you explain this disparity in production?


A. Even though almond flowers contain both male and female parts, some almonds require pollinators while a few others do not. Since you did not tell me the varieties I am not sure which you have.

Almonds in bloom at the Orchard in North Las Vegas
            It is possible that you have one almond tree which requires a pollinator while the other one does not. In order for pollination to occur the flowers need to be open at the same time. So if the almond flowers are not open at the same time it is possible that the tree will get flowers with no nuts produced.

            See if you can find out what the variety is and let me know. Once I know that, I can tell you a good pollinator to use. You probably do not want a third almond tree but maybe you can talk to your neighbors into getting one.

            The other option you have is to drive around town looking for another almond tree in bloom at the same time you're nutless almond is blooming. If you can find one in bloom at the same time, see if you can convince them to let you cut a few branches from their tree to supply pollen for yours.

            Immediately after cutting the branches, put them in a bucket of water directly beneath the nutless tree. This bouquet of almond flowers, providing it is a different variety, can act as a source of pollen for your tree. Otherwise, get rid of the nutless almond and put in Garden Prince or All in One almond variety which are self-fertile.

Who Stole My Almonds?


Q. I live on Black Mountain in Anthem in Henderson, Nv.  I have an almond tree about 3 feet high.  It must have had about 2 dozen almonds on it.  I woke up yesterday morning and all the almonds were gone over nite without a trace of hulks or shells.  What animal could have taken 24 almonds over nite? 


A. This is probably the culprit. As soon as I was ready to take his picture, he did this to me! The antelope ground squirrel.

Tuesday, August 14, 2012

UNLV Center BBQ, Plant Sale and Science August 23


The August UNLV Research Center BBQ, Plant Sale and Garden Talk will get underway on Thursday, August 23, starting at 6:30 PM with the BBQ and Cactus Sale. Garden talks featured will be Getting to Know Your Soil by Dr. Dale Devitt of UNLV and The Colorado River and the Future of Water by Dr. Tom Piechota. For directions or more information please call UNLV Biology at 702-895-3853. Click on it if you want it bigger!

Oleanders Drop Leaves in Drought. Will it Recover?


Q. I read the post on your blog on oleanders with interest. I too have an issue. My five oleanders are mature (at least 20 years old) trees.  When we moved here a year ago they had not been watered.   When the water was turned on and major landscaping installed, many of the leaves turned yellow and dropped. However the trees blossomed and continued to do fine. 
This is not the readers oleander but this oleander has leaf
scorch and leaf drop while the oleander behind it is
doing very well. Check the emitters or the source of water.
This is a good sign it is getting a lack of water.
            During the rains the gardener turned off the water system and sadly forgot to turn it back on. The water is of course back on but I have had to replace many bushes, although NOT the oleanders.  However they have begun to turn yellow again and are dropping leaves. There are still a majority of green leaves and the trees are about to burst into blooms. They have been fertilized, as has everything on the property, but I am baffled.  Would you be so kind as to give me your advice on what is happening and why?

A. Oleanders are so extensive worldwide that no one is sure where they originated from. Their climate of origin is important because it determines under what conditions these plants perform best but we do know quite a bit about how oleanders behave with and without water.
            We know that they are very drought tolerant. This means that when there is limited water, they can survive. Many plants can’t do this. Normally when drought tolerant plants first experience a lack of water the leaves will drop and the canopy will become sparse. If the water continues to be sparse the leaves they produce will be few and smaller and little new growth. They have to have a sparse canopy to survive.
            However when water is present they have the potential for using a large amount of water and are not low water users. They respond to this water by growing more, setting new leaves that are quite a bit larger and shedding the old ones. The plant itself becomes denser and flowers profusely (provided they are not trimmed with a hedge shears).
            Leaf drop is very characteristic in response to a drought. It is also characteristic when they receive water again after a drought. It is also characteristic of older growth to shed some leaves on older wood.
            So, in a nutshell, going from drought to abundant water expect some leaf drop. And when oleander grows normally, expect some leaf drop as the plant matures but not typically as much as during dry/wet periods. So is oleander a good pool plant? No.

What Do I Do? My Lawn Has Dead Spots in Summer

This lawn is starting to recover. Just the dead spots remain.
Wait until mid September or even October before you begin
to remove dead grass. Leave it there for mulch to prevent
weeds like bermudagrass from getting started.
If you had dead areas develop in your lawn and you are pretty convinced the damage has passed then it is time to wait until fall to repair it. Three types of problems lead to dead spots in the lawn: insects, diseases and irrigation problems. It is pretty easy to determine if the problem has passed. If it has passed, the grass surrounding the damaged area and throughout the rest of the lawn area will appear healthy and rapidly growing. All that will remain of the damage are the brown spots surrounded by healthy, vibrant, green grass.

Whatever you do, DON'T rake up the dead grass now and reseed or resod. Dead spots in a lawn are ugly. But what can be worse if you are not careful is to open up your lawn to a weed invasion, particularly bermudagrass, if you try to clean up these dead spots now. Wait. Wait until Fall, around mid September to mid October, to rake it up and reseed or resod.

If you try to reseed it now you will fail. Even laying sod right now will be difficult to keep alive. But if you rake up that dead area and expose the bare soil to sunshine and irrigation, bermudagrass WILL seed itself right into those spots. And then you WILL have a problem. Leave the dead grass alone and let it "mulch" or cover the dead area, protecting it from invasion by bermudagrass.

Powdery Mildew on Tomato... what to do?


Q. I have a problem with my heirloom tomatoes  the leaves on top have mildew on them what is causing this? I have never had this problem before. The plant is producing tomatoes and the leaves on top are still green.  I am baffled!
This is not tomato but it gives you an idea what powdery
mildew looks like. It looks like someone sprinkled the
plants with wheat flour
A. I would be very interested if what you are seeing is actually mildew and if you mean the disease powdery mildew. Powdery mildew is a disease that is very specific to certain plants. For instance the powdery mildew on roses cannot attack tomatoes.

Powdery mildews can attack numerous plants but each type of powdery mildew is specific to that plant. Powdery mildew is a common disease in desert environments because it can be very active under very low humidities.
The environment for this disease to occur is usually the same; somewhat shady areas frequently irrigated with overhead sprinkler type irrigations. This causes water to splash when it hits surfaces. This splashing water can carry the disease from one plant of the same type to a neighboring plant.
Nonchemical control of powdery mildew is the same for all types; reduce or eliminate the shade problem and the splashing water problem. Use drip irrigation. Improve air circulation among the plants by not planting too close together and don't let them shade each other. Give them some space and dont over fertilize them so they get real bushy and have alot of internal shading. Thin out the canopies of the plants to improve air circulation. Go to a different type of growing. Dont let them sprawl but stake them and tie them to stakes to get them more vertical and improve air circulation.
Usually if you can do all this you will not need a fungicide. Otherwise there are fungicides you can apply to keep it from spreading.

Japanese Blueberry Leaves Falling and Canopy Thinning


Q. My problem is with my Japanese Blueberry trees. Leaves seem to fall prematurely, browning and yellowish. One of the trees bark is peeling off and appeared to be dry. There are no visible insects but I do not know what to find anyway. I have spent so much money on them for them to die. Please help.
Not the readers but Japanese blueberries planted along a
block wall.
A. Japanese blueberries planted in a desert environment is like a square peg in a round hole; it will fit but you have to use a hammer. Japanese blueberries will require a soil heavily amended at the time of planting and organic mulch on the surface of the soil after planting.  It will do terribly in south or western exposures in full sun or in rock mulches. 
            If you planted this Japanese blueberry from a 15 gallon container then it will require about 15 gallons of water each time you water.  The amount of water must increase from this amount as the plant gets larger from year to year. 
            This can be accomplished by adding minutes to your existing irrigation schedule at each watering or adding additional emitters.  The frequency in the application of water, but not the number of gallons per application, will vary from season to season. 
            There is generally are a winter schedule, spring schedule, summer schedule, fall schedule and back to a winter schedule which means you should increase the number of times you irrigate per week about four times each year.  These schedules will coincide approximately with December 1, February 1, May 1, mid-June, mid-September and finally December 1 which completes the seasonal cycle. 
            Because your plant did not have the fullness that you would like, I would assume it is due to improper irrigation which may also lead to infestation with borers.  Pull off the loose bark at you see and look for damage in the wood do too boring insects.  This would include sawdust under the bark and perhaps elliptical exit holes from the trunk under the damaged area.  If the damage is more than half way around the trunk then I would replace the plant.

Monday, August 13, 2012

Yellowing of Meyer Lemon Tree Leaves Hard to Correct


Q. We went and talked to nursery folks a couple times about this tree. First we got the water cycle correct, then iron was suggested which we did as directed. Then a soil amendment was suggested. Online I read possibly the tree suffers from a magnesium issue. I thought these photos would give a better picture. We did as directed and the tree is not responding in fact it is getting worse. I am wondering if it is because of where it was planted which is a confined root growing area. Any insight would be appreciated.

Readers lemon tree with yellowing leaves
A. By looking at the leaves I have to assume this is a Meyer Lemon (which is, by the way not technically a lemon but an unknown hybrid found in a Chinese back yard by USDA researcher D. Meyer in the early 20th century).

Your pictures are all pretty good with the exception of not showing a critical view of the trunk where it is just out of the soil. Just for future reference always look at and show this interface of the trunk and soil. W/o that view I have to only guess that the rootstock/trunk union is well out of the soil and we can eliminate that issue. And, a shot of the soil might show how the plant is getting watered. I have to assume drippers and I would guess they are in the same locations as when the plant was planted.

Closer look at readers yellowing leaves
The leaves show two distinctive symptoms that often occur in concert: 1. There is some salt burn and 2. The common symptom that comes with salt issues is the magnesium deficiency. Just FYI Iron deficiency only occurs on the new leaves.
For the salinity (salt) issue we usually look first at the watering and with watering comes knowing if the water can even be applied uniformly all around the edge of the canopy, sometimes called the 'drip line'.

Citrus are botanically a shrub with shallow and wide spreading roots that are tough to grow to maturity with drippers unless they are closely spaced in a wide band around the canopy's edge. There is one picture showing the plant is right next to a step wall with no water being applied in that zone of the root system.

Clear look at the yellowing or chlorosis problem
on readers citrus
I would not worry too much about adding any supplements and see if you can begin to manage a watering system of application that would give a long deep soaking water application out near the drip line. The 'soaker' hoses could be laid out on the ground out near the drip line and let it run for hours and hours to try and leach out the excess salts that may have accumulated over time with the drip system. Drip systems are fine but, due to their limited water output salts can begin to accumulate thus impacting citrus' sensitivity to salts.

Give it a long deep watering about once every few weeks from now on all during the growing season (May through October)  to supplement the regular water to leach out the salts that inevitably are deposited with the limited volume of drip systems . .This leaching watering is also the great time to add fertilizer and get it into the soil evenly all around the active roots near the drip line.
-Terry Mikel