Most perennial flowering plants need to be divided every 3 to 4 years or they grow weak. Some perennials are just short lived and 7 years is about the average life span of a flowering herbaceous plant. I suggest you wait until spring and then dig up the plant, slice off a few young sections from the side of the clump, and toss out the old inner core of the plant. Replant these young starts into improved soil and fertilize with a slow release plant food like Osmocote. I suspect you'll be seeing plenty of blooms by next summer. Keep growing, Marianne Binetti