Question
I live in Fort Worth TX.  I have a 12 year old Chinese Pistache tree in my South facing yard.  It has never had beautiful fall color.  During the summer the leaves start turning brown.  This continues through fall.  If is some distance from other plants, but there is a large Mesquite tree nearest.  Could this be the problem?  Thanks!

Answer
Could be many factors  such as genetic or soil fertility but I do not think the Mesquite would have any effect. I would try fertilizing the tree this spring. Use a fertilizer called 10-10-10 at the rate of 1 lb. of fertilizer per inch of trunk diameter. Scatter this around the tree from about a foot from the trunk out to the edge of the extent of the branches. Water it in good but if you will apply the fertilizer just before a rain event you will not need to water. Thus will increase the foliage production and the minerals in the foliage.