I planted potentilla several years ago, and never cut them back (because I wanted them to get big). They seemed to do fine. Maybe you should let yours settle in for a full season, and cut them back next year.

I don't know about the burning bushes, although it might be too early for them to turn red. It's been a warm fall, they might need a frosty night to really turn on the color.

I can help with the burning bushes question. Young ones generally don't turn red the first season. When they *do* turn, the more sun they get, the more vivid the color. Also, it is a bit early for them to turn right now. I've notice a few leaves starting to turn red at this point, but that's all.

I dont know but mine has been red since the beginning of the October,it had a red tint most of the summer,maybe its just anxious!:)

Mine is STILL green. It's in the shade though. Seems they color earlier and last longer in full sun..... but I know mine will color up soon. It always does and the color is just as bright as the neighbor's bushes.

You don't have to cut back potentilla. You can trim it down or remove canes in late winter or very early spring before it leafs out to help it keep a dense shape.