I have two flowering crab apples planted 2 yrs ago beside each other (20 ft apart). When they went in they were identical. However for two years the one has flourished and the other is anemic, such that one has a 2.5 inch dia trunk and the other one has a 2.25 inch trunk. The most striking difference is the leaf size: the healthy one has many leaves 2 inches long and the anemic one has only a half the number of leaves about 1 inch long.
Is this a serious problem? Should I just wait for the weak tree to pull out of it?
Any suggestions for the weak tree?