>> I am just not sure how to treat my soil once I've pulled all of the flowers.
I have NO experience with Echinacea, so take this with enough grains of salt to season all the slug soup you're making.
If those mites DO overwinter in soil, one traditional approach is to grow no Echinacea there for a year, or for several years. Could you find something different that would look good here? And grow you Echinacea in a different bed?
If they do not overwinter in soil, that's a waste of time!
i wonder what growing conditions tend to favor or discourage mites? It might be easier to make them feel unwelcome than to kill every mite in the neighborhood.
By the way, once you have chopped or pulled all the perennials, and have an empty bed, it would be a good time to turn extra amendments like compost deeply into the soil. If that turns up weed seeds, you might want to mulch right after you till.
Maybe, instead of amendments, you could squeeze an over-winter cover crop like Winter Rye into the bed between now and frost.
Or if not a cover crop, lots of leaves that will decay by spring.
Or will you be sowing more Echinacea seeds right after pulling the old plants?
