what are the hardiest perennials
We are in northeastern Wisc and can have some long cold spells, well below -10 for days at a time. I have had only middling luck with my perennials. Coneflowers, red sedum, yarrow, black-eyed susans have done well; hollyhocks don't do particulary well for more than two seasons (they come back but do not bloom, even with fertilizer); and some ground covers have flourished. Larkspur, delphinium, carnations, peonies, etc, limp along, but after a brutal winter many things don't come back. Day lilies have done well in an area protected from the winds we have here. Suggestions, anyone, for the hardiest perenniaal varieities, preferably that bloom for a long period? Last year I tried some 'winter hardy' asters from Walmart that were supposed to be formulated for our area, but they didn't come back. I am trying to get away from annual planting, and develop a really resistant and sturdy perennial garden. The soil is rich and well fertizied and I try to follow instructions for mulching and covering different varieties, but I clearly need some help. We have some large shelter pines and low evergreens that afford some protection in the winter but the winds in our area are particularly forceful and unrelenting, and drop the wind chill down even further. We are seriously out in the country here and skunks will dig through whatever they must to get to bulbs. I have given up on bulbs as I would spend all my time fending off the wildlife, which is more resourceful than I am. Help.