Very roughly, find perennials beds go through maybe a five year cycle,
from looking scrappy when they're first planted to looking overgrown at the end.
The beds look at their best in the second or third year.
Don't think (at least here - (Cdn) Zone 5a) you can do a lot with perennial beds (re flowering) within six months.
If I need to do a quick fix on a perennial bed (or fill in an area for quick colour), I use blocks of annuals (e.g. geraniums).
Re Echinacea: find the older cultivars like 'Magnus' (pink), in picture, and 'White Swan' (white) to be very hardy.
I do periodically divide them and they last for years.
Some of the newer cultivars (in sunny locations) only seem to last here for a few years.
