Xtremehorticulture Blog Hits Near 30,000

My blog, Xtremehorticulture of the Desert, is approaching 30,000 hits per month. Judging from the number of hits this time last year, my blog should exceed 30,000 hits in the next one to two months.

Even though my blog has a focus on the Mojave Desert, these hits are coming from all over the world. Remember, these posts are focused on Desert Horticulture at 36,12 degrees north latitude at an elevation of 2,000 ft (610 meters) and should be adjusted accordingly for different locations.Pest and disease problems vary with locations as well.

I do not sell anything here (okay, maybe my coffee donation to help keep me awake when I get up early to do some posting. I like good coffee.). I will continue to recommend based upon my experience with products. I appeal to readers. If you have experiences to share please Comment at the bottom of the post. I review each Comment and if it is just a marketing effort then I reject it. If it adds something to the discussion, I will post your comment.

Growing Cherries Can Be a Problem in the Hot Desert

Q. From my Googling, it sounds like if I want cherries in this climate a good strain is royal Lee with Minnie Royal as a pollinator tree.  Do you know if they will grow and fruit well here?

A. Cherries produce erratically in the Las Vegas Valley. In some locations cherries produce abundantly and in other locations they produce almost nothing.

For instance, at the University Orchard in North Las Vegas we produced about 15 cherries in 15 years from 17 different varieties of trees. Virtually nothing. They flowered every year abundantly, there were no freezing temperatures after flowering that would eliminate fruit but the fruit failed to mature. In other words, the fruit failed to set.

However, some people in backyard locations here have produced cherries abundantly every year. Reports to me by homeowners are anecdotal but varieties that produced here include Bing, Lambert and a few others known to have a high chilling requirement.

In the Las Vegas Valley we don’t have enough cold winter weather to satisfy fruit trees with a high chilling requirement. Picking fruit trees with the proper chilling requirement for a certain climate is thought to be a cornerstone of good fruit production.

A chilling requirement is the amount of cold temperatures fruit trees should sustain during the winter in order to flower and produce a normal crop of fruit. Most research supports the concept that all fruit trees must satisfy their chilling requirement in order to produce fruit abundantly.

My observations at the University Orchard in North Las Vegas don’t agree with this universal concept 100%. When I interview homeowners about their abundant cherry crop and the location of their trees, one common theme seems to appear; cherry trees that produce fruit abundantly are located in areas where there is higher humidity such as near a lawn area or a swimming pool. Higher humidity may also play an important role for a good crop of Hachiya persimmons.

In my opinion the location of the cherry tree is more important than selecting a variety. My recommendation would be to locate cherry trees near a lawn area or swimming pool to improve your chances of having a good crop. Otherwise it’s a crap shoot regarding cherries regardless of the variety.

Is Bark Peeling on Mesquite Some Sort of Problem?

Q. I have a six-year-old, multi-trunked mesquite tree with bark that is beginning to peel from the trunk. It started last fall and is getting worse. Otherwise it is a beautiful tree and appears to be healthy but I am concerned I may be losing it. Any suggestions?

A. There are several different kinds of mesquite trees and it is normal among some of these for the bark to peel from the trunk as they get older. In some mesquite trees it is quite distinctive. It would be helpful if you knew which particular mesquite you have so we could determine if this is true of your tree.

However, peeling bark can also indicate a dead area developing underneath this area. You will not hurt any tree by peeling this bark back and looking more closely at the trunk. Inspect the trunk under the bark for possible damage and sap oozing from that location.

It is possible if the tree is watered too often that damage can occur to the trunk or limbs. Frequently damage from overwatering can also cause sap to ooze from the trunk or limbs. This damaged area of the trunk can lead to bark peeling.

If you peel off the bark and you don’t see damage underneath it, then assume it is natural for this tree at this age to have peeling bark and don't be concerned about it.

Is My Apple Tree Diseased?

Q. My apple tree has several different things going on with it and I’m wondering if it is suffering from some sort of disease. Other than that, the tree appears to be growing normally.

A. Let's cover these pictures one at a time.

First picture. The tree was damaged on the trunk but it is mending. You can see how the bark is beginning to roll back from that damage. It looks like the trunk was damaged either by sunburn or possibly borers. The damage stopped, the bark peeled away from the trunk leaving the dead interior exposed. Now the living part of the tree is growing over the top of the dead interior wood. The center of the trunk in all apple trees is dead. The only living part of the trunk is the outside cylinder that continues to expand year after year. This is nothing to worry about. Just keep the tree in good health and it will heal completely.

Second picture.  This is either some borer (insect) damage or a disease called crown gall. The only way to find out is to take a sharp, sanitized knife and dig down and see what's going on. If this is insect/borer damage then the bark will peel away easily and you will see evidence of this kind of damage under loose bark. You can go to my blog and search using the word “borer” and several postings will come up with pictures showing you what borer damage looks like when the bark is

removed. If this is borer damage, then remove all of the loose bark and allow the tree to mend itself in the same way it did in the previous picture. If this is crown gall it is not a serious problem. Don't cut it out or worry about it. It will not be a big problem for the tree in the future. It just looks ugly and it will get larger over time.

Third picture. This does look more like crown gall. It does not look like borer damage because it is on the underside of the limb. Borer damage usually occurs on the upper surface of a limb or on the side of limbs facing West. Very seldom do we see borer damage on the underside. Take a sharp, sanitized knife and see if any of that bark is loose and can be removed for closer inspection. If not, leave it alone and it will not be a big problem in the future.

Fourth picture. This looks like sun damage in the crotch of a limb. It is also possible there are borers in that spot causing some damage. Take a sharp, clean knife and remove any dead bark down to the wood. Allow the tree to heal over that area.

Borer Damage to Fruit Trees Best Corrected Now

Q. I have a peach tree planted in 1998 with the bark lifting from the trunk easily. My gardener doesn't know what this is or how to treat it. Can this tree be saved?

A. This is borer damage to your peach tree and is the usual reason for their death at an early age. The damage is done by an immature stage of a beetle. Some people called them "worms" but they are properly called larvae.

The adult female beetle flies looking for a mate during the spring and summer months. Once she mates than she lays eggs on many different kinds of trees including fruit and many landscape trees and shrubs.

It appears she is attracted to trees damaged by a lack of water or intense sunlight on the limbs. Reducing damage to the tree because of intense sunlight is thought reduce damage by boring insects.

This is done by “whitewashing” limbs, particularly on the upper surface, with a mixture of white latex paint and water in a 50/50 mix.

Whitewashing these limbs reduce, but do not eliminate , damage created by intense sunlight. If you look closely you will see most of the damage is either on the upper surfaces of these limbs or on the sides of limbs that are facing south or west. These directions are where the most intense sunlight comes from.

When pruning peach trees in particular, which seem to be very susceptible, try not to prune so much out of the tree that it lacks the shade needed to protect the limbs from intense sunlight. Here are a couple of postings on my blog.

http://xtremehorticulture.blogspot.com/2015/08/identifying-their-damage-and.html

http://xtremehorticulture.blogspot.com/2014/02/mechanical-control-of-borers-in-fruit.html

Trees that get borers sometimes go into a death spiral; borers continued to attack these limbs or more limbs, limbs die and open the canopy for more intense sunlight which causes more damage which attracts more borers.

There are no safe insecticides or chemicals that you can apply to these trees to cure the problem. The best approach I have found is removing the damage from the trees with a very sharp knife and let the tree heal on its own.

Pruning Oleander into a Multi-Trunked Tree

Q. I have two, 7 foot tall oleander bushes about 8 feet apart. Can I turn them into trees by cutting all the branches to the ground except for the largest, fattest branch in the middle? I know the suckers will be a problem for a while. Also, is it safe to grow a small vegetable or herb garden between them? Is oleander flower and leaf mulch safe around the edible garden?

                    

A. Yes, you have the right idea. Oleanders can make very nice small trees but the suckers at the base will be a problem for several years.

Oleander pruned to a multi-trunked tree and in bloom.

They can be made into a single trunk or a multi-trunked tree. Multi-trunk trees are easier to manage. Select 5 to 7 stems, or branches as you call them, coming from the base and going in different directions. Odd numbers of branches are more pleasing to the eye than an even number. Those are the stems you will keep. They should be large and vigorous.

Oleander suckering from the base when pruned as a multi-trunked tree.

Remove all other stems as close to the ground as possible. A reciprocating saw with a pruning blade is an easy way to remove them than a saw or loppers. Remove side branches from the stems up to a height that looks good to you. The trunks should be cleaned of side branches. Make sure you cut these side branches as close to the trunk as possible. Clean the trunks anywhere from 2 feet up to about 4 feet.

New stems will sucker from the base throughout the growing season for several years. This is because oleander wants to be a shrub. You are forcing it to be a tree so it will try to revert back to a shrub.

As soon as suckers emerge from the base, remove them by pulling rather than cutting. If you pull them when they are very new they are easy to remove. Removal by pulling causes fewer suckers in the future than cutting them.

Oleanders are poisonous but research from California demonstrated that leaves and stems can be composted and returned to the soil without problems for other plants including vegetables. 

http://slosson.ucdavis.edu/newsletters/Downer_199829067.pdf