Q. I have a butterfly bush in my garden, but need to replace it every two years. What is the proper care for a butterfly bush? Are they only supposed to last 2 years? (Zone 6a, Kingston, Ontario)
A. Buddleia is marginally hardy to zone 5.
It has a better chance of surviving our weather with a good layer of winter mulch; however, wait until the first hard frost before putting down the extra mulch.
There is another species, B. alternifolia, that is reportedly more cold hardy than B. davidii. You might give that species a try.
Lake Simcoe South Master Gardeners