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.

More about deep root fertilizer applications

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.

Some Recommended Vegetable Varieties for Fall and ...

Recommended Vegetable Varieties for Fall and ...: Our garden group got together this past Saturday and started putting together a recommended vegetable variety list for the Mojave Desert. So...

Viragrow Delivers!

Fig Fruit Drop May Be Lack of Water

Q. After reading your suggestions I have a feeling the problem could be not enough water.  What do you think?  I have been watering three times a week for 1 1/2 hours (8 gal. each hour) for a total of 12 gallons each time. I took a picture of the fig tree so you could get an idea on the size of the tree.  As you can see the tree is mulched.

Readers fig tree

A. A very reliable indicator that a fig is not getting enough water is poor fruit development. Fig is a very resilient plant when it comes to water and can withstand fairly droughty conditions. But one of the first things a fig will do when water is limiting is hold back on fruit production or produce fruit that is not “juicy” because that requires lots of water. 

Figs produced along the Brown older wood. This is the first crop produced on the wood from last year. This is called the Briba crop.

Fig fruit will be small and tough if not enough water is applied. When water is withheld even further then you will see the results in growth. At this point fruit production is no longer in the picture much but rapid and wild growth will be curtailed. Figs need new growth for fruit production. The more growth it has, the more fruit it will produce on this new growth. New growth becomes the source of fruit production this year and early fruit production (Briba crop) next year. Once fruit production is over you can pull back on watering but it needs plenty of water when fruit is being produced.

 

Figure leaf yellowing and leaf drop can be a sign you need to give more water

It is hard for me to tell if your watering is adequate or not. The frequency, three times a week, sure seems enough. The quantity of 12 gallons each time sure sounds enough for a small tree like that. Without going down to the roots somehow and seeing if the soil is moist or not we are just guessing. Mulching helps but a small amount of mulch around the trunks a couple of feet in all directions and an inch thick will not be enough most likely. I like to put down mulch at least four inches in depth and have it out as much as the edge of the canopy (where the growth stops) to be effective.

But the proof is in the pudding. If fruits are not swelling up to a good size and full of water my guess is that something is keeping the water from getting to the fruit from the roots. Either not enough is applied or often enough or there is something stopping the water from getting to the fruit such as root damage, trunk or limb damage, disease or insect problems.

Parrys Agave Good Choice for Mojave Desert Landscapes

Parry’s Agave

Andrea Meckley, Certified Horticulturist

andrea.meckley@aol.com

 
Description:  Evergreen succulent
Mature size: 2’x 2’
Flower:  with aged plants
Water use:  low
Exposure:  all day sun
Origin:  Arizona, New Mexico, and Northern Mexico

Parry's Agave

Hardy:  to 5 degrees F
Uses:  Landscape accent plant, potted plant

One of the many hardy agave species for our southwest landscapes and gardens is Parry’s agave (Agave parryii).  The grey green leaves grow slowly as a compact rosette.  Adding interest are patterns of indentations of previous leaves showing on the back of each new leaf.   In late spring to early summer old Parry’s agaves, 20 years or more, produce a twelve-foot stalk of blooms that can grow four inches a day. Hummingbirds are attracted to the flowers which begin as red or pink buds, opening to a bright yellow bouquet.  The plant dies after blooming but during its lifetime produces offsets assuring more plants will replace the original.   Planted in groups or alone this plant is attractive in the succulent garden, in pots, or in the landscape.

Readers Success with Sago palms and Saguaro in Las Vegas

After reading your column in the R-J for 10/25-26, specifically your response to a question about Sago palms, I thought I would share my Sago success with you. To summarize, the main plant in the 1st picture was started from a "pup' off of a neighbor's plant in La Verne, CA, in 1972.  

The 2nd pictured tree began as a "pup" from the 1st one.   I kept both trees in 5-gallon rolling redwood tubs with full exposure to afternoon sun.  When we moved to Tucson, AZ in 1994, the tubs went with us.  I then moved the trees out of the tubs and into the ground where their exposure was pretty much limited to the morning sun.  When we retired and decided to relocate to Las Vegas in early 1999, both trees were moved back into redwood boxes and made the relocation with us.  After substantial changes to our new backyard in Las Vegas were completed in early October 1999, I once again moved the trees into the ground.  For esthetic reasons, I have allowed both trees to keep "pups" of their own.  These trees have a main exposure to the south and receive direct sun all day.  

The 3rd picture is a view looking from the WSW and captures both trees.  I think they are both doing quite well.

Another plant we are quite proud of is the Saguaro cactus shown in the last photo.  This plant, which was in the ground at our new LV home in early 1999, was just under 2 ft tall.  During the course of our backyard remodel, this plant was moved 2 times before its present location while being very careful each time to maintain its "clock" orientation...lessons learned from our Sonoran desert experience.  The rear fence is 5-1/2 ft tall to give you a perspective of the trees's height today.  You will also notice the arms that have emerged...4 that you can see with 2 others on the far side.

I trust you will find this Sago success story interesting and enjoyable.

Reader Success with Celebrity and Beefmaster Tomatoes in Las Vegas

I received this email from a reader who wanted to tell me about some of his successes. The following are his successes with some of the pictures he sent to me.

This year I planted Celebrity & Beefmaster, one each in hanging planters and one each in our little raised garden.  I can tell you the hanging planters are a waste of time and money.  We got maybe 6 or so tomatoes off the two plants and none were even 3" size.

Readers Beefmaster tomato in small raised bed

In our raised garden the other two plants gave us a pretty good harvest with tomatoes from late June to early August.  I think I need to put even more straw for the Celebrity.  The Beefmaster gave us actually bigger tomatoes and they gave us more, but they sometimes were a strange shape, although the taste was great.

Readers Celebrity (smaller, round) and Beffmaster tomatoes

What I really wanted to relay is the story about the tomatoes shown in the photo.  These were picked a few days ago in early October.  As I said the plants were planted in early April, I was late this year.  They stopped producing around mid-July.  I was going to remove them and put in new plants but ran out of time as we left for travels to Europe in late August. Surprise!!  

When we returned 1 Oct these two plants had continued to grow (see other photos in separate emails) and were bearing new tomatoes as shown.  The plants are huge, probably at least 10 feet in height/length, leaning over due to the weight.  The Celebrity has produced the smaller tomatoes.  The Beefmaster is still producing large tomatoes, but they do have shapes just a little different than beefsteak, but they do remind me of such.  Served some at a dinner party last weekend and all were amazed at the get taste.

There are still at least 12-15 tomatoes on these two vines, currently all green, bit they continue to ripen.

i just think it great to continue to have fresh vine ripened tomatoes this time of year.

Desert Green Conference for Landscape Professionals Nov 6-7

Desert green conference for professionals will be held on November 6-7 at the Henderson Convention Center. Tell your gardeners about it and encourage them to attend. There are many good presentations made to help local gardeners become better at their profession.

Click here for more information about the Desert Green Conference and Regisrtation

Click here to see the conference agenda and Registration

Chinese Pistache Leaves Curling

Q. I have a Chinese pistache tree which is nice and green but the leaves began to curl. I spoke to someone at the nursery where I bought it, I did what they said but I am not seeing any change yet. Can you help me save my tree that cost me so very much money when I had them plant it last year?

A. Chinese pistache is a tree that does very nicely in our desert climate with very few problems. One thing that it hates is a soil that stays wet.

Curling leaves on pistachio can be an indicator of a water or insect problem. Once the leaves are curled however, these leaves will not straighten out again. However new leaves that come out should be normal if you have corrected the problem.

Curled leaves can indicate water stress; not enough water in the soil or watered applied to often. If watered too often, curled leaves can be an indicator of root rot or trunk rot at the soil level which is called collar rot which results if the soil is kept constantly wet or it is buried too deep.

Whatever you do, be sure not to water this tree daily! You will kill it if you do. You are far better off giving it more water than it needs, but applying less often.

The amount of water to apply depends on its size. How often you applied the water depends on the time of year. In midsummer you should not be watering more often than three times a week. For desert adapted trees like this one you should be able to get by on one, or at the most, two watering's in one week.

I wish I could tell you how many minutes of water to apply but water does not work in minutes, it works in gallons. If your tree is watered by drip irrigation, you should have four drip emitters around the tree.

Once the tree is above 10 feet, you should be adding more emitters around the tree. The emitters should be no closer than about 18 inches from the trunk.

If the problem is from insects feeding on the leaves and causing them to curl, a systemic insecticide intended to be applied to the soil above the roots should kill the insects. The leaves that are curled will stay curled. You will not see normal leaves until you see new growth. 

Eggplant Beautiful Bush No Fruit

Q. I have grown plants in whiskey barrels every year with a good harvest. This year my eggplants have grown bigger than ever, beautiful, look healthy and have lots of purple flowers but almost no fruit. Since planting it's just been one giant flower bush. Why is it not producing fruit?

A. I am guessing it is a combination of probably three things; variety, weather conditions and general care. Stick to varieties of eggplant that have done well for you in the past. Don’t just buy any eggplant off the shelf and expect the same results. Varieties are important.

Purple Thai eggplant, a good variety for the Mojave desert if you like Asian style eggplant

Secondly is the weather. At very high temperatures many vegetables will fail to set fruit. This is because the pollen may become sterile at high temperatures and the fruit will start to develop and fall off. Some varieties are better at setting fruit at high temperatures than others.

Thirdly is soil enrichment and fertilizing. If your soil has been amended with a good quality compost prior to planting then I would not fertilize with any nitrogen fertilizer until I saw fruit developed that was a couple of inches long.

Eggplant forming fruit in July

If the soil is enriched heavily with good compost and then we fertilize the plants with high nitrogen fertilizers we can end up with wonderful vegetable bushes with little to no fruit.

I would suggest you mulch the plants as well. This will help keep soil moisture more constant. If soil moisture goes up and down during the day, the plant may drop flowers or fruit as well.

Less likely is a lack of bee activity. I am guessing your bee activity has been about the same as previous years so that it is not likely to be the problem.

Azalea Problems in the Desert

Q. We have an azalea planted on the northeast side of the house.  At this time of year it gets no sun. The tips of its leaves are brown.  What needs to be done?

A. Azalea is a very difficult plant to grow in our climate and soils. It likes soils on the acidic side, with lots of organic matter in the soil, absolutely hates salts and salinity, does not handle direct sunlight very well at all in the desert, in short it is one of the more difficult plants to grow here.

That being said, I also planted one about 30 years ago in a very similar exposure. It did the same thing as yours and that is the leaf tips turned brown or died after about three years.

If you are going to try and make this work to any degree at all your exposure would be okay but you have to modify your soil with lots of good compost, finally ground sulfur or aluminum sulfate to help lower the pH of the soil and wood mulch.

Make sure you have enough water surrounding the plant so that the soil doesn't dry out. If this were my plant I would push any salts out of the soil surrounding the roots by letting the hose slowly run water around the base of the plant for several hours so it is completely drenched. I would wait two or three days and do it again.

The purpose of this is to push out any salts that may have accumulated around the roots. I would check to make sure that there are enough drip emitters, if that's what you're using, to thoroughly wet the soil around the plant every time it irrigates. If not, I would add some.

Next I would lightly dig in around the base of the plant some good compost mixed with finely granulated sulfur and some iron chelate.

Next I would look for a specialty fertilizer for azaleas and fertilize the plant lightly this fall. If this were a water-soluble fertilizer I would mix it in a bucket of water and pour around the base of the plant. I would repeat the fertilizer application in the spring.

Finally I would cover the soil under the plant with a couple of inches of wood chip mulch. The old believes that have scorched tips will remain on the plant until you get some new growth and they finally drop off.

Read another point of view about azaleas in the desert

Wormy Artichokes a New Problem?

Q. What is the worm or caterpillar that attacks artichoke plants and how do I control them?  I had a beautiful artichoke plant last year and had four or five great artichokes from it right away. Then the worms (caterpillars) struck and were all through the artichokes. I cut it down and it came back beautifully but now the worms or caterpillars are eating all of the leaves.

A. This is most likely either damage from armyworms or loopers. I am guessing that it is probably armyworm.

It doesn't matter which one, the control measures are the same just the timing could be different. The usual time we see damage from armyworms is either in the spring of the fall. They can attack the leaves or the flower buds. Loopers crawl along like the cartoons of caterpillars where the midsection “loops” up in a curve. Armyworms don’t.

Spinosad as a liquid that can be attached to a hose for an application.

You would use either a spray of Dipel, Thuricide or Spinosad. All three of these sprays are considered organic and do a very good job on these types of critters. Their death is not immediate but they do stop feeding a very short time after these sprays come in contact with them. They will die a couple of days later.

BT in the form of Dipel as a dry, flowable insecticide. This one must be mixed in water and constantly stirred or agitated to keep it suspended.

If you see them now, spray. Mark your calendar for next year and spray when you first start to see damage. You can apply a preventive using your calendar as a guide when to apply.

Bt in liquid form

These sprays are good to have around since they can be used to control a number of different “wormy” pests on tomatoes, peppers, eggplant, grapevines, fruit trees, petunias and many other plants.

Read more about pest management in artichoke

Fall Or Winter Head Cold or Allergies? Shoestring Acacia.

Shoestring Acacia is in bloom right now and has been credited with allergy problems. In fact, they will bloom through most of the winter.

Shoestring Acacia flowers in Bloom in January

Shoestring Acacia can grow up to 40 feet tall quite rapidly and it is relatively upright so it can be useful in more narrow locations and in scale with two-story homes and commercial buildings.They are good selection for desert landscapes but allergies might be a problem.

 

Shoestring Acacia with a fairly wide form.

It is propagated from seed so there is a lot of genetic variability which means you can have narrow ones and you can have wider ones. If you are picking one that is intended for a narrow area, pick one that has a narrow habit to begin with in the nursery. Chances are if it is narrow in the container it is more likely to be narrow when it is older. If you pick one that is not so narrow when it is small, you do run the chance of having a fairly wide Shoestring Acacia.

 

Shoestring Acacia, narrow form. This tree is started from seed so there is a lot of variation in the trees. Pick one that is narrow to begin with and hopefully it will stay narrow if that is what you want. If you want one that's wide, then pick a form that's wide in the nursery.

It hails from Australia which, like so many trees from Australia, blooms during the fall or winter months rather than spring and summer. It is popular here in the desert Southwest and some people consider that it might be over planted.  There are complaints from people that it is messy and the leaves, because they are long and narrow, are difficult to clean up. Whatever you do, don't cut the top off. Trees that are pruned like this are ruined for life.

Shoestring Acacia topped at commercial planting North Decatur and CC 215

Bob Morris Q and A at Viragrow

Bob Morris Q and A at Viragrow Monday and Friday M...: Viragrow asked Bob Morris to answer your horticulture questions at Viragrow's office in North Las Vegas each Monday and Friday mornings. ...