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Saturday, May 27, 2017

Brown Branches Are Dead Branches?

Q. Do brown branches denote "deadness" on a tree in the spring or can they be brought back somehow?
Dead branch in purple leaf Plum that will not come back because it is truly dead.
Italian cypress with brown branches that appeared dad but are still alive. Nothing will grow from these brown branches anymore even though they are alive.
A. Brown does not always mean a branch is dead. Some tree branches are more brittle than others. For instance, fig, persimmon and pomegranate branches can be quite brittle compared to apple and peach.
            The usual method I use to see if a branch is dead is to bend it. Many branches of trees may look brown and dead but are quite supple when bent. Supple and bending denotes it’s still alive. Other trees have branches which are alive but can snap easily when bent. In cases like this I scrape the bark with my thumbnail or a knife to see if the wood is green under its “brownness”.
            Remember, some plants are slow to leaf out in the spring. Wait for new growth and prune out whatever might be dead. I sometimes get confused as well when winter or early spring pruning.

White Cotton on New Growth of Ash

Q. I have a 6-8 yr. old ash that has this white powdery looking substance on the newer growth. Can you tell me what it is and how to eliminate it. Photo attached.
Unknown white cottony insect at base of new ash growth.

Another image of white cottony insect at base of new growth on ash

A. I have to admit I put this on a back burner because I wasn't quite sure what was going on. I have seen this on vegetables and herbs but never on the new growth of ornamental trees. It is most likely an insect problem.

These insects are feeding on the soft, succulent new growth. If you touch this white fluffy substance on these shoots I think you will see these insects beneath it. The problem I had was what to call these insects. At first I thought it was woolly Apple aphid which makes a lot of sense in the cool time of the year when there is new growth.

But what troubled me was that I have never seen woolly Apple aphid in Las Vegas before. I have seen it in other cooler climates.

See some pictures of Wally apple aphid

Secondly, the pattern that they are feeding in does not typically fit woolly Apple aphid. They don't usually feed all along the new growth. They are typically clustered at the bottom of the new growth. Until you tell me differently, I am going to stick with woolly Apple aphid or another kind of insect that feeds on the sap of newer, soft, succulent growth.

They are easy to control or even ignore. You could take a hose and a nozzle and knock them off with a powerful, directed spray on the foliage. If you want to be more aggressive, you could use a soap and water mixture and do the same thing with a hose and applicator. If they really bother you, you could nuke them by applying the Bayer insecticide for trees and shrubs and apply it to the soil surrounding the roots. In my opinion that is overkill. See if they continued to be a problem or not. Aphids typically become less of a problem as temperatures get hotter.

Wednesday, May 24, 2017

Stop the Quail From Eating Apricot Leaves!

Q. How do you stop Gambel's quail from eating apricot tree leaves? They never touched my 3-year-old tree until near the end of the last growing season then they swarmed the tree and chewed at everything that was green. These little fish poops ate all melon plant sprouts yesterday as well. I tried hanging CD's, strips of tin foil to no avail.
Bird pecked peaches at the Orchard

A. About the only thing I can suggest is giving them an alternative to munch on or cage them out using bird netting. I am sure there are lots of suggestions from people like spraying garlic, hanging pie tins or DVD’s to scare them but in my experience these tricks do not work for very long or not at all.
Electronic bird scaring device used at the Orchard. It would work for about two weeks. After that, the birds got used to it.
            Birds in general can be a real problem, particularly to the fruit. The other option is to let them eat the leaves and let the tree replace what is lost. Once you get past spring, hopefully, they will move on to other more tender leaves at your neighbors.

Too Much Shade on Tomatoes Equals No or Poor Fruit

Q. We are growing the Celebrity variety of tomatoes in our garden here in Las Vegas and decided to cover them this year with a mesh tarp for shade because the sun has scorched them in the past.  However, we noticed the vines are growing but the tomatoes are not very big and they are not ripening like they usually do.  Are they supposed to have complete sun? What do you suggest?

Providing too much shade causes poor growth and reduced fruit or flower production or none! 30% shade vs 60% shade.
A. The amount of shade that you provide to tomatoes is critical for continued production of fruit. Shade cloth is typically categorized by the percent of shade that it provides. For flowering plants you should provide no more than 30 to 40% shade or they may stop flowering and setting fruit. Plants that do not flower can handle more shade, up to about 50 or 60%.
            You didn't tell me what percent shade you are giving tomatoes but I suspect it's too much. Light shade, 20 to 40%, is hard to find locally. Usually you have to order light shade for crops. You can provide shade by also using lathe instead of shade cloth.
            In northern climates we used to use snow fence. To get 50% shade, remove every other lathe from a solid ceiling of lathe. To get 25% shade, remove two and leave one. Chain-link fence with PVC slats gives you about 75% shade. I think you get the picture.

Remove Suckers from the Base of Citrus

Q. You mentioned that citrus trees are often grafted. Are full size trees grafted like dwarf trees? Do I need to remove anything? The trees are about five feet tall. Will I have more success getting fruit from full size trees?

Remove suckers like these from the base of small trees as soon as you see them.This fruit tree is watered with drip irrigation from in-line tubing. Wood chip mulch is covering the soil.The tree was planted bare root and painted with white wash to prevent sunburn.
A. All citrus bought from a nursery are grafted, full size trees as well as trees sold as dwarf or semi dwarf. Seldom are they grown on their own roots for a variety of reasons. The most common is because of our cold winter climate and protecting the rootstock from freezing. Some of this benefit from freezing is passed on to the rest of the tree.
Root stock dogleg on grafted fruit tree.
            Fruit produced from dwarf trees can be the same size as standard size trees if the tree is managed properly. If you look at the bottom of the tree you will see a “dogleg” where the top tree was grafted to the to the roots of a different tree. You will see this dogleg on many ornamental trees as well.
            Anything growing from below this “dogleg” (on the rootstock) should be removed as soon as you see new growth. Young trees frequently “sucker” from this rootstock and these suckers must be removed. Pulling them off rather than cutting them is better. As the tree gets older, it frequently stops suckering as much.
            Enjoy what you can. Citrus is “iffy” in our climate. Some years you will have fruit, other years you will not. Some years they may freeze to the ground and other years sail through the winter without damage. 

Avocados in the Las Vegas Desert?

Q. I am trying to grow an avocado tree.  I have it in a container and it's now 22 inches tall.  When is the best time to transplant and what is the best way to take care of it in our desert?

A. As you are probably aware, avocados are “iffy” in the Las Vegas climate. Probably a little worse than citrus regarding surviving winter cold. It depends on which avocado you are growing. 
            With that said, I would put the container in a protected area away from extreme cold during the coldest part of this coming winter. Around the first week of March, I would plant it in the ground. Make sure you amend the soil and do not fertilize it after August 1.


Daily Watering of Young Lemon Tree a Good Idea?

Q. I'm considering watering my little lemon tree every day during the summer months. Is this good or bad? The tree dropped two-thirds of it's leaves a month after planting. That was three months ago. It has stabilized, and I currently water it every other day on a slow drip. (4 gallons per watering) Should I water every day in June, July, and August because of the 100+ temps?

A. I have noticed some problems with citrus the first year after planting from containers into the soil. There was a lot of relief yellowing, leaf scorch, leaf drop and some dieback. This happened even though there was wood chip mulch at their base. Once small amounts of water were applied daily they did quite a bit better during the summer.

You will not have a problem watering every day if the soil drains water quickly. You will have a problem watering daily if the soil holds water for a long time. You might see some advantage to watering with small amounts of water every day. I see that sometimes on very young citrus but only for the first year after planting. I'm sorry to say, "it just depends…".

If you have not done it, try applying 3 to 4 inches of wood chips around the bottom of the tree and you should be able to water every other day with no problems even on the hottest days.

How Important Are Chilling Hours for Fruit Trees?

Q. This is really great information that you put on your blog!! Thank you so much for doing this, and it gives me a bit more hope about expanding my home orchard in Phoenix. 

How many chill hours are you getting where you are located? Specifically related to Pluots, you are recommending some with some pretty high chill hours, such as the Flavor Supreme which is listed on DWN as 700-800 chill hours. But as you mentioned above that may have a lot to do with location and micro climate.

Also for Apples, Pink Lady is a pretty late ripener, and I’ve heard that late harvest don’t do as well in the extreme heat of Phoenix, something similar to where you live. But again, I'm hoping the placing them is certain cooler places within my backyard and trying to create a micro climate that is a bit more forgiving to these fruits could have a large impact as well.

Would love to hear you take on the points point. Thanks again for putting some much time into this.

A. Thank you for appreciating the hundreds of hours that it took over a period of one and a half decades to put this list together. Many kudos to the Master Gardener volunteers who supported it.  I will try to address each of your questions separately.
            Most of the trees used were donations by Dave a Wilson Nursery, Tom Spellman in particular, who worked with us since 1996. This orchard is located in North Las Vegas Nevada at right about 2000 foot elevation.
            The orchard is exposed to the North West by cold winter winds which helps explain why citrus was not included on this list even though it was tried. Las Vegas is not citrus country but many people further south in the Valley have had success with some citrus and even limes and blood orange in warm microclimates.
            Our chilling hours are somewhere between 300 to 400 hours per year. You are exactly right. If you take chilling hours literally many of the recommended trees should not produce in this climate yet they have for over 15, now going on 20, years. Some of these so-called high chilling hours tree fruits have shown no sign of a lack in chilling hours.
            Tom Spellman was the first person to bring this idea to light for me. It challenges many preconceived ideas about chilling hours and there has been much speculation and even disbelief in this information.
            Personally, I believe that chilling hours are more important in some types of fruit and even some varieties than others. Is chilling hours important? Yes, definitely. Have we followed chilling hour recommendations to literally? Yes, definitely.
            Too many, Phoenix and Las Vegas have similar climates if you don't live in either of these locations. You and I both know that as far from the truth! Phoenix is a totally different animal from Las Vegas but I believe there is a wide variation in how plants view this difference. I believe most apples are more prone to chilling hours than peaches, nectarines, apricots and plums and their crosses.
            I don't know all pink lady apple performs in Phoenix but it is an outstanding Apple in the Las Vegas area. Like pomegranates, this particular Apple seems to have better flavor quality as temperatures drop. In our harsh desert climate it seems to develop a thicker, tougher skin but the flavor quality of the "meat" is superior. It is worth giving a try in Phoenix, Yuma, Parker, Bullhead or Lake Havasu.
            I think planting apples in areas of the landscape that avoid the late afternoon sun is a good idea. Contrary to some information out there, if your soil has lower amounts of organics in it, amend it with compost at the time of planting. I also believe you will see huge benefits if the soil is covered with wood chip mulch under its canopy to a depth of at least 4 inches.

            Keep the mulch away from the trunk for the first five years of the trees life to avoid collar rot. If rabbits are problems, protect the tree from rabbit damage with 1 inch hexagon with chicken wire for the first five years as well.

Tuesday, May 23, 2017

Furry White Things on My Myers Lemon Tree

Q. Last year we bought a Myers lemon and planted it in a large pot. We got more than 30 lemons off this little tree. I noticed a lot of sap near the base of the tree, then a bunch of furry little things on the trunk and some branches. They scrape off easily. I’m guessing they are the cause of the sap.
Cottony cushion scale on lemon

More of the same

A. You are right. This is cottony cushion scale, an insect, on your lemon tree. Those little furry things are homes to the scale insect. They live under those furry things where they are protected from pesticides and predators.
            Once in a while they come out and build a larger, furry home or find a mate. When they do, this is called their “crawler” stage, when they are most vulnerable to pesticides and predators.
            What’s interesting are the ants that you didn’t mention. These small, scale insects feed on the sugary sap inside the tree. While feeding on this sugary sap, a sugary concoction comes out the other end which some ants love.
            These ants move these insects to new growth in the spring where feeding is a lot easier than at the tough, woody base of the tree. In these new locations, ants “herd” them like cattle and protect them from marauders.
            From your picture it doesn’t look like you have very many on this tree yet. Take some alcohol and a cotton swab and dab them off. If there were lots of them you could spray horticultural oil several times during the year, particularly during tree growth periods.
            These oils suffocate the crawlers and keep it from spreading while the older ones eventually die off. Apply these oils three or four times during the year at times when temperatures are cool. By the way, it also helps a lot to control any ants in the area.