Question
I planted 4 Aristocrat trees in my front yard, and 1 of them has leaves that look like its fall and their changing color, but there not falling off. They are red in color and look just like the season is changing, the other 3 trees and green and full of leaves ??

Answer
Steve:

If I am picturing your trees as you describe, this phenomena has been occuring on the ornamental pears (callery) for the last few years, more so over the last 2.  Our plant disease clinic has looked for a disease organism on numerous ocassions, but have come up with a goose egg so far.  Other surrounding states have seen the same thing.  Most of my colleagues feel that there may be several possibilities, all dealing with the type of tree that we are dealing with--things like root stress and graft incompatibility. It all seems related to a general weakness of the tree, seeming shows up as they get older as well.  Some of these trees continue to go down and succumb to the problem. All I could suggest is to be sure it is being watered well during the hot/dry summers.  Water it deeply, but infrequently. If the trees are new transplants, be sure to pay attention to the water and avoid any injury to the trunk from string trimmers and lawnmowers. A soil test may be useful as well.

Regards
STeve