Apricot Leaves Dried-Up in Midsummer

Q. A few days ago I noticed that most of the leaves on my apricot tree had withered and turned brown. The same thing, to a lesser degree and later in the season, happened last year. But in the spring it brought forth an abundance of blossoms and fresh, green and healthy looking leaves and produced lots of good fruit. I checked the soil, and it is not dry, but slightly moist. I am watering daily on a drip system for 35 minutes. So, wondering if you have any idea what is causing this and if I should be concerned.

This is most likely NOT borer damage. Borers typically ravage a single limb. This is over most of the tree. That most likely puts the cause in the trunk, roots or soil.

A. I looked at the pictures and 3 things come to mind right away. These center around daily watering which is a no no, the rock mulch I see around the tree and the possibility that not enough water is being distributed to serve all the roots. I don't know how much water you are giving the tree but I think the tree is running out of water before the next irrigation. I also think the rock mulch under the tree is terribly hot.

First, is the rock mulch. I like rock mulch when it is used around desert plants. I don't like rock mulch very much when it is used around non-desert plants such as fruit trees. I think you would help the tree a lot if you could rake back the rock a distance of about 3 or 4 feet from the tree and put a layer of 3 to 4 inches of wood chip mulch instead. You can get this free in North Las Vegas from the University Orchard or from Cooperative extension just south of the airport.

Daily watering of trees during the summer is not a good thing. If you can apply more water to the trees and then wait one day before your next irrigation it would be helpful. Tree roots begin to suffocate when water is present in the soil all the time. Giving the soil a chance to dry and admit some air to the roots can be quite helpful to the tree.

When the tree is watered, water should be applied to at least half the area under the canopy of the tree. This may require you to add more drip emitters then you have. A tree that size should have at least 5 to 6 drip emitters and would do better if there were more than that. These emitters should be placed about 2 feet apart under the canopy and about 18 inches from the trunk. 

A tree that size probably requires about 15 to 20 gallons every time you water. This means if you have 6 drip emitters, they should be 3 gallon per hour emitters if you are watering for one hour. If you are watering for 30 minutes, you should use 5 gallon per hour emitters.