Invigorate perennials for next year by dividing them now. It’s a good idea to do them before they die back because you can still identify them. The ground is also still warm enough for the replanted divisions to root out before the winter. Leave more fleshyrooted perennials, such as hostas and red hot pokers, until the spring.
CUT the old flower stems back then dig up the clump, along with plenty of its surrounding soil and lift out from the bed. You can keep paths and lawns clean by making the divisions on a tarpaulin. PUSH two forks into the clump back to back but with the prongs alternating. Make sure the forks both have a good purchase on the root system. PULL the handles away from each other to split the clump. Pull them back in again to separate the pieces. You could use an old knife, sharp spade or even pull loose clumps apart by hand. REPEAT the process to get smaller clumps and select the best, youngest growth from the outside of the clump to replant. The old centre can be discarded.