I really want to grow some Butterfly Bushes. I have two new ones on order from Wayside that are supposedly hardy in zone 4-a purple one and a pink one. I would love to be able to grow some of the "regular" ones like Black Knight, but they aways die on me after the first year. Has anyone been successful overwintering them in zone 4? Did you do anything special for them (winter protection)? I would like to grow them in a garden that's fairly protected with an eastern exposure. It gets full morning sun and some shade in the afternoon.
I have friends in Dassel who have had a buddleia for a number of years. One thing to remember, Buddleia is VERY late to break dormancy. Many years, their bush does not appear until the 2nd week of June, depending on how warm a spring we have. In zone 4a, Buddleia is treated much like a perennial, the shrub dies back to the ground each winter and sprouts new growth in the spring. This is okay since buddleia blooms on new wood. I would suggest that you mulch well AFTER the ground freezes, not before. You may need to try the plant in a few spots before you are successful.