I would absolutely not cut them back at this time. They are still in the recovery mode from the transplanting. Those leaves are how plants manufacture new roots and help our plants make and store energy.

Pruning will, of course, trigger a flush of untimely growth for these plants that will then be forced to halt root development activities in favor of growing a bunch of new top growth.

You would really be causing some problems for these plants. Somebody is bound to tell you that forsythia are tough as nails and nothing will set them back. Don't listen.

This post was edited by rhizo_1 on Sun, Jul 21, 13 at 21:22

Best to cut them back hard after they bloom in feb or march