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Thursday, December 3, 2015

Nopal Cactus Talk Thursday, Dec 3 Lorenzi Park

Mexicans call them Nopales or Nopalitos. The fruit they call Tunas. These edible cacti were under evaluation at the University Orchard in cooperation with the University of Sonora in Hermosillo.
Fruit or tunas of the nopal cactus under cultivation and evaluation at the University orchard

I will be giving a presentation to the Cactus and Succulent Society on how to grow them as a food crop Thursday night, December 3, at 630 pm at the Garden Clubs building located at Lorenzi Park off of Washington and Rancho.
Nopal cactus ..nopales...under cultivation and evaluation at the University orchard. This is an ideal size and thickness to use as fresh vegetable.

Apple Variety Testing for the Mojave Desert

Q. I've seen Yellow Newtown Pippin listed as Under Review in your recommended fruit varieties to grow in the desert. How has it done? I would love to have one if the quality is good here.

A. Here is a link to the recommended fruit variety list that I completed back in 2010. 
http://xtremehorticulture.blogspot.com/2015/11/special-fruit-tree-orders-no-longer.html
Apple Babe from Dave Wilson Nursery under evaluation in North Las Vegas Nevada

Fuji apple grown in North Las Vegas Nevada
Anna apple grown in North Las Vegas Nevada
When I left the University back in 2011 this program of fruit evaluation for desert environments was no longer continued. Fruit quality is very connected to the terrior or the local environment. This is nothing new and has been noted for many other crops where quality is a desired trait and useful in marketing.

I have not had a chance to evaluate this Apple yet. I like about five seasons of production to get a good evaluation. Just because a plant grows does not necessarily mean the fruit quality is high. Sometimes there is little you can do to influence the quality of a fruit if you do not have a suitable terrior it. 

Most people think that a good fruit is one that is large, has an appealing color and free from blemishes to be a "good" fruit. How wrong! There are too many variations because of the climate and weather. The chilling requirement is 800 to 1000 hours according to Dave Wilson Nursery. This may be somewhat problematic for production in the warm desert but not necessarily for fruit quality.

I will take a look at some of the information the orchard has gathered so far on this variety and let you know. I have not been involved so I hope that the three is still there, there are replications to account for variations and data has been recorded. It ripens a little bit before Granny Smith and a month or so before Pink Lady. It ripens during a time of the year when flavor should be good considering ONLY the time of year. 

More information on this and related varieties.

Tuesday, December 1, 2015

Texas Mountain Laurel Good Choice for Desert Landscapes


Blond Ambition Ornamental Grass Good for Las Vegas Landscapes


Why Did My House Plant Suddenly Begin Wilting?

Q. Suddenly, this plant started drooping and weI can't figure out why.  It's was a beautiful healthy plant until about a week ago when the branches started to bend/droop. We tried tying it up but this morning it was even worse.  Could the heat being on in the house be a factor?  We've had the plant for about seven years with no problems. Two other possible factors:  about a month ago we moved the plant from an inside wall to an outside wall near two windows; and about four months ago we re-potted it using a regular mix.

Plants that are drooping are wilting inside the house

A. I don't believe anything that happened a few months ago would have any direct bearing on this drooping. It has to be something that happened recently or that has been progressive. I'm assuming you've monitored the soil for moisture content by either using the pencil method or lifting it to determine its weight before irrigating.

My guess is the problem is at the root level or major stem or stems coming out of the soil. I'm guessing the roots. I would pull the plant out of the container as if you are repotting it. Remove the soil from around the roots and inspect the roots for damage. It is difficult to find repotting soil that is not free from fungus gnats. If there are insects feeding on the roots than this could be the problem.

If the soil is not draining like it should and root rot becomes a problem, then you would see this kind of reaction. I would repot it with a good potting soil, stake it, add some super thrive (I am not a big believer but at this point I would try anything) and see what happens.
Inexpensive soil moisture meter. Not terribly accurate but gives you a general idea if the soil is wet or not.

Monitor the soil moisture content carefully with a soil moisture meter you can get from the nursery for about eight dollars or use these other methods I mentioned to determine soil moisture content before you irrigate.

Correcting Oleanders with Leaves Browning Along the Edges

Q. We have one oleander approximately 2 years old and 4 new ones we purchased several weeks ago.  The older one (1st photo) and one of the new ones (2nd photo) have some leaves that are browning along the edges while the centers are still green; a few have tips that are browning too.  From what I've read, could the plants have leaf scorch or, "salt or boron toxicity"?


Two pictures sent in regarding oleander leaf scorch

A. You are right, this browning along the margin of oleander leaves, or leaf scorch as it is sometimes called, could result from a number of things.

One possibility is a bacterial disease that has been called Oleander Leaf Scorch. It is a bacterial disease which is rarer in plants than fungal diseases. This disease is carried from plant to plant by what we call "vectors". These vectors can be insects that feed on the "juices" of this plant or they can be transmitted by humans on pruning shears. This is why I am constantly reminding people to clean and disinfect their pruning equipment before they begin pruning and between plants if the plant they finished pruning appears to be "sick".

More information about oleander leaf scorch from the University of California

Leaf scorch can also because to buy a lack of water and excessive salts in the soil which can be made worse if plants do not get enough water. One particular salt that you have identified as a problem in our soils is boron. The other particularly troublesome salts contain sodium and chlorides. Salts that contain for plants, such as nitrogen, phosphorus, potassium and others can also cause leaf scorch if they are in excess. Fertilizer salts containing high levels of nitrogen can be particularly troublesome and cause plant damage if applied in excess, too close to the plant or when soils are dry.


What to do? Apply compost around the base of the plant and either wash it into the soil or lightly dig it into the upper surface of the soil.

Add more water. If you feel as if the plant is not receiving enough water, add more drip emitters. This is preferable to just increasing the number of minutes since everything watered by that valve will be affected. If you're fertilizing the plants, make sure the fertilizer salts that you apply are kept at least 12 inches from the trunk and applied near the emitters or bubbler. Make sure the soil does not become dry between irrigations because dry soils increase the concentration of salts already in the soil.

Lastly, cut the oleanders to the ground and let them re-grow from the base. If you apply more water, improve the soil and are careful with fertilizers and the plants still have leaf scorch during the next growing season, then dispose of them and to get new ones. Oleander leaf scorch will not be in the soil. It can only be transmitted from unhealthy plants to healthy plants either by insects or humans who are not careful about pruning.

NOW Two Locations for Fruit Tree Pruning Classes in December

A second site has been added to the pruning classes; the UNCE Learning Center.  All classes begin at 845am and conclude by 100pm.

I will be giving free fruit tree pruning classes to the public on Saturdays and Tuesdays in December. Classes will be held at the UNCE MG Demonstration Orchard and UNCE Learning Center. The UNCE Master Gardener Orchard is located 100 yards east of the intersection of North Decatur and Horse Road. Horse Road is located 2.8 miles north of the Bruce Woodbury Beltway in North Las Vegas. 

The UNCE Learning Center is located at 8050 Paradise Road just north of the intersection of East Windmill and Paradise (east of I-215). Bring your pruning shears, loppers and saw if you have them.

Pruning Class Schedule for all Locations
8:45 AM   Preparing your equipment for pruning
9 AM   Peaches and Nectarines
10 AM   Apricots, Plums and Their Relatives
11 AM   Apples and Pears
12 PM   Pomegranates, Figs, Persimmons and Nut Trees

Pruning Class Locations
Saturday, December 5     UNCE Orchard
Tuesday, December 8      UNCE Learning Center
Saturday, December 12   UNCE Orchard
Tuesday, December 15    UNCE Learning Center
Saturday, December 19   UNCE Orchard
Tuesday, December 22    UNCE Learning Center




Holes in Trees

Q. I have three pecan trees in the Moapa Valley area that has been attacked by something for the last six years after they were planted. It starts with small circular holes, 2 or 3 millimeters in diameter, in the bark.  This holes are often in a line extending horizontally across the trunk or limb.  Then the bark appears to be shredded in concentrated areas.  As the summer season progresses, the tree leaves slowly and progressively turn prematurely brown.  I never see any particular pest on the tree, just evidence of their presence by the damage they inflict.

This same problem seems to affect a plum and nectarine tree which are now dead. One of the trees was affected so badly that I cut the tree off just above the graft about 4 years ago.  It has regrown some limbs and has not yet shown evidence of new pest damage.  The other two pecan trees still show evidence of continuing damage.  I used the Bayer borer worm treatment two years in a row a few years back.  That seemed to help a little, but again, over time, the damage has been recurring. I think I am going to loose another tree soon and all of them eventually if I don't figure out how to fix the problem.  I'd be willing to try replanting all new trees if I could have some confidence that the problem would not reoccur.  Any information or advice you can offer will be appreciated. 

First picture showing bird damage
A. The first picture is for sure damage from birds in the woodpecker family, probably sapsuckers. The second picture is most likely the same but the damage is spaced so closely together it is more difficult to recognize. The third picture is some sort of "mechanical" damage, the same type of damage as the first two and I can only guess that it is from the same thing using the KISS principle.

Second picture showing bird damage very close together and causing a lot of damage
Most of these birds are migratory so you see their damage in the spring usually but it is also possible it is in the fall. I am no ornithologist but I understand their are some birds in this family that live in this area permanently. I only see this damage during migrations but maybe in your location it might be different.
Third picture doesn't show the bird damage as well but I'm guessing this is what is causing this kind of damage

I have had damage to fruit trees for dozens of years and the trees survive and don't seem to be bothered this much at all. I think the reason for that is they grow so rapidly that they recover from this damage quickly.
Williamson's sapsucker might be causing this kind of damage. I no longer have the photo credits for this picture but I took it from the web several years ago.
From the looks of the trees and the environment I can see in the pictures I think your trees are under a lot of stress. This may prevent them from recovering quickly from this damage. It is very important that trees that are damaged get enough water, fertilizer and soil enhancement so recovery is quick and not lingering into succeeding years. They must recover completely in one season of growth. They will do that if they are pushed to do so after the damage has been done.
Sapsucker damage to an Apple at the University Orchard
Each of these holes put into the tree from birds by their feeding must totally heal before the next season of damage. I don't think yours are doing that. Cover the soil beneath the trees with wood chips at least four inches deep and out to a distance equal to the ends of the branches. Water and apply fertilizer sufficiently after you see the damage to push the tree's recovery as quickly as possible.

If you can use a bubbler and basin instead of drip (if you are using drip irrigation) this might help. This will flood the area under the trees and deliver enough water for a quick recovery. Fertilize the trees in late January or February to get the trees into rapid growth before the damage occurs.
Bubbler and basin around a fruit tree with the basin covered in wood mulch
You can also try to put wire mesh around the tree or damaged areas of the trunk but the birds usually then go to limbs. But if you lose a limb at least you don't lose the tree.


Bees and the Care of Fairy Duster Plant

Q. Please help me identify the bees on this fairy duster shrub growing on the Eastern side of a Mesquite home. Additionally, I'd appreciate some pointers on how to help this plant become a healthier better looking shrub. Very little has been done because the bees are usually on it. The bees and I coexist with a healthy respect for each other. I'm hoping they are some type of honey bee.



Pictures of plant sent to me
A. Bees can be difficult to identify through just pictures and I am not an entomologist so it makes the problem worse. Size is probably the first clue to the type of bee. Next is the coloration. When we get into the general size of the honeybee it can get a little difficult whether these bees have been Africanized or if they are leaf cutter bees.
Basil and leaf cutter bee
The other category is whether they are social bees or solitary bees like the leaf cutter. Nearly all of the bees are beneficial whether they make honey or not just because they are our best pollinators. Some bees can be a problem such as the Africanized honey bee or leaf cutter bees.
Bee swarm in a fruit tree
If honeybees have been Africanized they can be aggressive and dangerous. This is the only be that we would consider to be truly dangerous. Other bees of this size like the leaf cutter bee can be a nuisance because it cut circles out of the leaves of some plants such as basil, roses, lilac, bougainvillea and others. Normally these leaves are soft and easily cut by the leaf cutter bee so the female can use it for nesting. Solitary bees normally do not make honey that we can collect. Social bees are the honey makers.

Regardless, all of the bees you are seeing there are friendly and beneficial.
Pollinating peach flower

Fairy duster plant is native to North and Central America growing in warm desert climates and soils. This tells you a little bit about how to manage it. It will tolerate desert soils as well as infrequent watering.

At planting time I would amend the soil with about 25 to 50% compost and make the whole about three times wider than its container. I realize yours is already in the ground so watering and fertilizer applications are important to mention.

Do not water this plant too often. That will be the biggest mistake people make.Fertilize it lightly once in the very early spring around late January or February with a rose type fertilizer. The plant can get 3 feet wide and 3 feet tall in soils that have been amended with compost.

As long as it's in a sunny location you should see a profusion of blooms in the spring and summer months that attract bees, hummingbirds and night flying moths. Quail like to feed on seed from the seed pods. Rabbits like to browse on new growth.

You can clean up the plant in the early spring by removing dead leaves and stems. You will encourage more blooms if the plant is in a sunny location and flowers are removed before they begin to form seedpods.

Chinese Pistache Growing Poorly

Q. A nursery planted my tree in spring (May I think) it has sap running in several places from the trunk. Also the leaves seem to have some disease, but the new leaves at the base of the trunk look great.  I have looked on the internet but could find an answer.  It looks like it's dying.  What is your prognoses - see attached photos taken today.
Trunk of this Chinese Pistache
A. I looked at the pictures of the pistache tree that you sent to me. The pictures make me think it is water related. Your Chinese pistache is probably a grafted tree. A graft is used to attach two plants together; one which will become the roots and the other becomes the trunk and top of the tree. If you look at the trunk of the tree a few inches above the soil you should see a slight "crook" or bend in an otherwise straight trunk. This bend is where the graft took place which joined the two young trees together.
Picture of leaf sent in

This is important to find. If the new leaves you mentioned at the base of the trunk are coming from below this crook or bend then the tree is "suckering" from the plant grafted for the roots. This is a very good indication that the top part of the tree has been damaged or is under a lot of stress. Normally, this is not a good sign and you don't want this type of growth to continue. You would remove this growth from the trunk and is close to the trunk as possible. If you leave any short stubs after you remove these suckers then growth from this area is likely to return.
Base of trunk showing new growth
What caused this? This is where I go out on a limb, no pun intended. Nine times out of 10 this is related to some sort of watering issue. I am going to guess and say it's not getting enough water. If this was a 24 inch boxed tree you should be delivering about 15 to 20 gallons of water each time you water. I am guessing this tree is on drip irrigation. I can't tell you how many minutes this would be because that will depend on how much water these emitters are delivering. A tree of this size should have a minimum of four drip emitters spaced in a square pattern about 18 inches from the trunk. If I am correct, you should be able to correct this problem by building a basin or bowl around the trunk about 3 feet in diameter and 6 to 8 inches tall. You would use a hose and fill this basin with water completely once a month during the winter months. When things begin to warm up in about March you might do this every two weeks. Once you hit may you should be doing it weekly.
Chinese pistache shown in its location
Another possibility could be that it is receiving too much water. If you are watering daily and delivering a lot of water through those drip emitters than it is possible the roots are suffocating because of too much water. I tend to believe it's not enough judging from how the tree reacted.

What to do? Build that basin around the tree that I mentioned earlier. Fill this basin with water from a hose twice. Remove the suckers from the tree as I described. If you think there are not enough emitters, add emitters around the tree or find some way to deliver a higher volume of water if you are only watering a few minutes. You won't see much of a reaction from this tree to these improvements until next spring and summer. Remember, do not water daily. When you do water, give it a lot of water and wait a few days between irrigations during the summer months.