Valygirl, you have waited a long time for someone to respond.

I don't know much about shrubs. My yard is barely big enough to get the pickup turned around in so that I can head off to other property to grow an annual garden. One fruit tree, perennial plantings and a few hydrangeas . . .

Here is what I've learned just searching around the internet and there is very little information on Rhus trilobata care. It is almost as tho' they should be "care-free." Altho', Wyoming and New Mexico Cooperative Extension mention Rhus trilobata, the only extension service that talks about pruning is Harvard. Well, I guess they aren't an extension service . . .

"R. trilobata requires little maintenance; pruning to control height and improve appearance can be done as needed." How about that?

Since the pruning information on Staghorn Sumac all seems to be about doing that work after flowering, I'll guess that is also true for Rhus trilobata. Pruned branches tend to die-back with winter frost damage anyway.

The Harvard info is linked below. Hope it helps!

Steve

Here is a link that might be useful: arboretum.harvard.edu