Leaves Cupping on Pistache Tree

Q. I planted this Red Push pistache in the fall and it has put out a lot of new growth this year. My concern is that the leaves are curling. Would you advise me on this?

Red Push pistache planted and staked

A.  Your tree looks very healthy and green. I would not worry about it much at all. A close look at the leaves shows there is some minor scorching along the edges of the leaves. Scorching on the leaf edges when the leaves are first coming out is enough to cause these leaves to begin to roll or curl as you call it. Leaf edges are damaged but the rest of the leaf continues to grow causing it to roll.

Be careful not to water too often. It's okay to water daily for the first week or 2 but after this you should not be watering daily. When this tree was planted the soil should've been thoroughly flushed with water. 

Leaves cupping because the edges were damaged when young but undamaged center continued to expand

If this has not been done, do it now by putting a hose with a sprinkler on the end of it with a very low volume of water coming out and flood that area under the tree for several hours. This helps flush any salts out of the soil in the area of the planting hole. When the tree was planted a hose should've been used to fill the hole as the roots of the tree was being backfilled with soil.

A tree of this size might require at least 4 drip emitters located about 18 inches from the trunk. You must water the soil in the planted area. A tree this size might require 10 to 15 gallons each time you irrigate. Next year it might require 15 to 20 if it puts on some good size. Next year, add 2 more drip emitters if you are only using four now.