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Tuesday, November 4, 2014

Don't Expect Third Crop from Figs

Don't expect to get that third crop of figs from your fig tree this fall in our Mojave Desert climate. In the Las Vegas climate of the Mojave Desert figs just do not have enough time to produce that third crop. If we had extended warm weather through November we could get that third crop. The third crop will try to form but it sits there as young immature figs because the weather is cooling down to rapidly. There is no way to get that third crop without global warming or building some type of greenhouse enclosure around the tree.

Third crop of figs that didn't make it from a previous reader

Problem With Chitalpa after Deep Root Feeding

Q. We are having a major problem with one of our two chitalpa trees after they were fertilized. We were told by professionals that these are desert trees and don't require a lot of water and the watering schedule has not changed for 2-1/2 years. They are on drip irrigation with each tree receiving 5 gallons of water a day scheduled at 2 AM, 6 AM and 10 PM.
We had a tree service company do a deep root feeding on May 14th because one tree looked sickly while the other one was healthy. After fertilizer was applied the healthy one now has leaves that are brown, curled up and falling off. The tree service came back out and suggested to water the tree for an hour for two consecutive days just in case the fertilizer put the tree into a shock. We did that with no change in the trees except for new shoots growing from the trunk of the damaged one. The tree service doesn’t know the problem. Should we plan on replacing this tree in the near future or will it come back next year?
Chitalpa not the readers
Chitalpa not the readers

Chitalpa not the readers
A. Desert trees need water just like regular trees but their main claim to fame is that they need irrigations less often. 
Let’s explore what happened. First of all, 5 gallons of water a day is not enough water unless they are very small trees, perhaps no more than 5 feet tall.
Secondly, there is no reason to apply the water at three different times when using drip emitters. Drip emitters apply water very slowly so the entire amount of water can be applied at one time with no problems.
I think you may have been a bit misled when you purchased these trees. Many people, including professionals, do not understand the relationship between the water use of desert trees and the level of acceptability these trees have when different amounts of water is applied.
Chitalpa with limb dieback, probably watering issue, not the readers
Just because trees are so-called desert trees does not mean that they can get by with very little water. Chitalpa is a desert-adapted tree, not really a true desert tree like some of the acacias and palo verdes.
I do think your damaged tree resulted from the fertilizer application to the soil. I don’t think there was enough water present in the soil to dilute the fertilizer enough to keep the roots from getting damaged after the application.
Secondly, I believe the soil water taken up by the roots was so high in fertilizer salts that the leaves were damaged and the severely damaged ones fell from the tree.
What can you do? Flood the area under the tree with water once a week for the next three weeks. After this, go back to normal irrigations using your irrigation system. I would look closely at the possibility that you may not be applying enough water during an irrigation.
If you suspect this might be the case, either increase the number of minutes so that more water is applied or add more drip emitters under the canopy if you suspect there are not enough. You will increase the amount of water either way. The key consideration is whether you are applying enough water under the entire canopy or not. If you suspect you are not, then the only solution is to add more emitters.
What will happen to the tree? Because of leaf drop you may have some branch die back and lose some limbs. Let the tree continue to grow this summer and fall and don't do any pruning until this winter.

This winter see if you can do some corrective pruning to improve the shape of the tree. If the tree has been to severely damaged due to die back, then you might consider replacing it. I don't think you can make that determination for another month or two.

Plant Lantana While Soil Still Warm

Q. Is it better to plant lantanas now or wait until Spring?

Lantana with spring growth

A. Now for most of November is a great time if you can find them. Make sure to amend the soil with good compost and water thoroughly each day for several days in a row and then turn it over to your drip system. Before they start growing next spring, cut them back to about an inch and a half above the soil, fertilize them and give them a good drink.

Precautions When Planting Peach After Borers

Q. You recently identified that my peach trees had borers in them. I found the oval larval holes under the loose bark. Can I plant a new peach tree where I removed the afflicted tree? If so, are there any preventive measures I should take?

A. There is no problem planting in the same hole. This insect burrows into the tree, not the soil.
However, make sure you whitewash the next tree with either tree whitewash made from lime or dilute white latex paint, or nearly white latex paint, not an oil-based paint, with about the same amount of water and apply it to the trunk and main scaffold limbs.

Prune the tree so the canopy shades as much of the trunk and scaffold limbs as possible. Make sure the tree receives adequate water and if you can apply 3 to 4 inches of a woodchip surface mulch the tree will perform better and have less stress.
Peach tree with whitewash and mulch
Make sure you keep surface mulches a safe distance from the trunk so it does not cause it to rot from excess moisture. That has a known history of good performance in our desert. You can go to my blog, extremehorticulture of the desert, and search for recommended fruit tree varieties if you don't have one in mind.

This borer can fly and comes in from other infested trees including many landscape trees and shrubs in the area. Sunburn or sunscald is the main culprit so providing shade on the trunk and lower limbs and giving it protection from whitewash helps reduce sunburn. Good luck.

Velvet Mesquite Favored over Chilean Mesquite

Q. I want to plant a mesquite tree but I’m not sure whether to buy a Chilean or a velvet mesquite.  Do you have an opinion on these two trees?

A. Both trees will do well in the Mojave Desert climate. They both have a similar shape and size, tolerance to winter cold but there are a few differences.

Wikipedia on velvet mesquite
Chilean mesquite

Chilean Mesquite is also called thornless Mesquite. So a major advantage of the Chilean Mesquite is supposedly its lack of thorns. However, I have heard of it developing thorns later in its life.
Chilean Mesquite is faster growing then velvet Mesquite but this can also be a disadvantage. Sometimes Chilean Mesquite grows so rapidly its canopy can become top-heavy and may suffer during severe winds and get uprooted.
Chilean also tends to throw a lot of its energy into top growth rather than a good balance between root and top growth.
Winter form of young mesquite
Velvet Mesquite grows rapidly but not as rapidly as Chilean Mesquite. It has much more balanced growth where it develops a good deep root system along with good canopy development.
Sometimes Chilean Mesquite will develop a lot of surface roots and not develop the deep rooting that mesquites are famous for. Velvet Mesquite on the other hand does develop a very deep root system if you will encourage it with good soil preparation and deep, infrequent waterings.
I tend to favor velvet mesquite over Chilean Mesquite even though it has thorns. Pruning its structure early in its youth will go a long way to having a beautiful tree later on.
Mesquite blown over due to shallow irrigations
As I said, water these trees deeply and make those roots “chase” the water so it establishes a deep root system. Don't be afraid of water stressing these plants to the point where they start to shed leaves during the summertime and then give it a good deep watering.
You should put this tree on a valve with other desert adapted trees and shrubs with deep root systems.

Why Are My Pomegranate Seeds White?

Q. This is my first year growing pomegranates. I harvested three. The first two I picked too early because the skin broke and I didn’t want something to go after them. I expected them to be red inside. They weren’t. They were an off-white color but they do taste good and sweet. Did I pick them to green?

A. The best time to pick pomegranates are when they are sweet. We use visual indicators or a calendar to tell us when they are ripe. These visual indicators include fruit splitting. However, they can split early if they get irregular irrigations or after a rain.

There are varieties of pomegranates which ripen in September and others we are more familiar with, like Wonderful, don’t ripen until about Halloween.
Ambrosia pomegranate

Some varieties like Utah Sweet don’t get red inside. They are the color you are describing but they are sweet. Others, like Wonderful, will be bright red inside.
Pomegranates come in a wide variety of colors

You were right in picking when the fruit splits. Even if it’s too early they will get destroyed by vermin or disease once they split. By picking it you prevented vermin from getting the arils or seeds. Great job! Mark your calendar for next year’s harvest.

Worm Exodus Due to Environmental Irritation

Q. In the last 10 days we have experienced a major worm exodus out of our yard onto the sidewalk. I recently applied a lawn fertilizer with no pesticides in it. One of these die-offs was after a heavy watering and one was after no water for 2 days. Is this normal this time of year?

A. It is hard to pinpoint the reason why worms did a death march out of your lawn but the usual reasons are because they can't get enough air or some irritant is applied to the lawn.
A lack of air usually occurs because the soil is kept too wet, like right after a heavy rain, or is compacted from traffic or heavy equipment. This can be corrected by aerating the lawn once a year.
It is possible that a heavy application of fertilizer might irritate them enough so they would leave. Most fertilizers are salts.  If the soil becomes salinized this could be enough of an irritant for earthworms to try an evacuation.
Quick release fertilizers (these are the most inexpensive types) easily dissolves in water so fertilizer salts are released into the earthworm environment very quickly. Next time apply a fertilizer that has half of its nitrogen in a “slow release” form. This releases the nitrogen more slowly, as well as the salt content, and is easier on your worms.

It is also a better fertilizer for your lawn. Slow release fertilizers encourages moderate growth and is applied less often. Quick release fertilizers tend to “jolt” the grass into rapid growth and then disappears quickly.

Delay Pruning Mockorange Till Late Spring

Q. I have three dwarf mock orange plants near each other growing in rock mulch. Two are a beautiful dark green. One has brown leaves on half the plant.  My landscaper says the cause is sunburn.  If so, do I pick off the brown leaves, let them stay on until they fall off, prune the whole plant or what?

A. Yes, rock mulch is a frequent culprit in poor growth of mock orange. Its poor performance is due to sunburn and sun damage but this type of damage is accentuated by the rock mulch.
Organic mulches like wood chips and the addition of compost to the top of the soil improves the health of these plants. Improved health helps these plants handle tough locations. When plant health declines they can't handle these types of locations very well and thus they burn and scorch.
The reason for it being on one plant in three is probably because the others time is coming. It is just beginning.

Yes, you can cut them off or remove them but wait until spring unless it is really ugly now. If you remove leaves now you're going to see a bunch of bare branches. Do you want to see bare branches or ugly leaves? Your choice.