The key to growing this prairie perennial plant is good drainage and lots of heat. It is the wet that rots and kills them in the winter not the cold. These members of the aster family are also known for being short lived so if you keep them alive for 3 or 4 years consider yourself lucky. I suggest you grow them on a slope or raised bed and add some boulders around the base to absorb more heat. Now here is the hard part. This plant needs moist soil as it becomes established and die quickly if the soil dries out. Once the roots have grown down deep, they are drought tolerant. You can divide the plants every few years and don't worry about feeding them as they tolerate poor soils. In your cool, maritime climate Echinacea are a challenge to grow but the spectacular colors and upright form of these perennials make them worth the effort. Keep growing, Marianne Binetti P.S. You may have good luck growing them in a large container them moving the pot under the eaves of the house during the wet winter.