Question
We have a chinese pistachio about 4 years old.  I have noticed that many of the leaves are turning yellow and are curling.  They also feel somewhat dry to the touch.  We have had unusually high heat lately and the tree is planted in a lawn on our front yard with a slope away from the tree.  There is another chinese pistachio tree (about 12 yrs od) 30 feet downslop from this tree. I am afraid our tree is deceased and also concerned that I may not be watering enough--would this be a cause?  The "downslope" tree gets a lot more water than this one because its at a location where the water drains to and kind of puddles when I water the lawn.  I am going to water the "problem" tree more to see if it cures the problem but I also want to take other action if needed. Thanks.

Answer
Hello Arturo,

It is quite possible that the problem is simply due to drought and heat.  In my experience, Chinese Pistache trees are somewhat shallow rooted, so their roots do not penetrate as deeply as some trees.  This means that they will be more likely to show stress from drought and heat than other trees.

I would encourage you to water the tree more frequently, especially during periods of drought and high temperatures.  The watering will not cure the leaves that are already dried, but hopefully you can prevent additional leaves from drying out.  If you notice areas of dead wood, you may want to remove these twigs or branches by pruning during dry weather periods.

One other suggestion is that if you tree does not have any type of mulch, you may want to add a mulch layer under the tree.  Mulches help hold moisture and can be quite beneficial.  Also, if there are any plants under the tree (grass, ornamentals), they will compete with the tree for moisture, so it will be more difficult to keep the tree adequately watered.  You should consider keeping the area under the canopy of the tree plant-free to help this young tree.

Good luck!
--Jen