Stressed crape myrtle

I bought a pre-bonsai crape myrtle this summer, still in a nursery pot. It did well, despite our wicked heat this summer. In fact, it bloomed. Two or three weeks ago I noticed some leaves were beginning to turn yellow or red. Some days later many ants were crawling in the tree. I guessed they were herding aphids. So I sprayed with spectracide, figuring that would take care of the bugs as well as any possible funguses. The bugs are gone, but the foliage change continues. New growth looks stunted. The plan is to put the tree in a large training pot at the end of October. Is this a sound plan, or has something gone terribly wrong requiring immediate attention? Thanks to all.

Beth

Hi Beth,
It is good to see You post on here.
Some of my Crape Myrtles look that way this time if year every year. The are tough plants in our area and do well here, I think it will be fine to do as You have planed.
Ken


PS I sent You a PM.