Although tuff under drought Summacs are not really "drought tolerant" as lets say Mesquites ... Palo Verdes for example ... sounds like the branch is damaged somewhere ... if the plant was water stressed you would expect to see water stress over the entire plant starting at the leaves on the outside edge of the plant from the tips inward ... not single branches ... wind damage ... a damaged limb ?? ... Texas Root rot is known to effect Rhus lancea in Sunset zones 12 and 13 ... is the root zone soggy ?? ... in root rot the leaves stay attached as they wilt ... get some local advice.

Good Day ..

Thanks for the comment.

The Symptoms are perplexing. The affected trees are multi-trunked and have similar symptoms. Bark has loosened and fallen off and there is no growth on some trunks while other trunks on the same tree are not affected. I assume cause is lack of moisture. I have since water deeply and pruned the affected trunks. There is now vigorous new growth is at the base and along the lower ends of the affected trunks. But the new growth along at the outer reaches has curled substantially, becoming bronze-like and in some cases has completely collapsed but still remains on the tree. I am going to submit a root sample to the county authorities for pathological examination.

Here in phoenix, I also get mixed messages on sumacs being drought tolerant. I thought mine was until the former owner of my house drove by and asked why we hadn't been watering it because it was not on the verge of death.

My friend has one in central phoenix and claims it loves to be watered especially in the summer.

My opinion - give it more water and fertilizer.

We have two huge ones that need to be watered every month in the summer, but hardly need anything when the weather cools off.

I have 3 multi trunks in las vegas total western exposer 2 are doing great 1 the leaves are a light green and looks kind of wilty. It gets the same amount of water as the other 2. any idea whats wrong?