Answer: In my experience it is better to wait until spring to do any pruning because the branches help somewhat to protect the crown from winter damage. In spring though you will want to cut it down to about a foot high, shorter if needed to remove winter damage. Also, based on your zip code you are gardening in zone 5A, the coldest part of zone 5. Depending on your microclimate, it could be as cold as zone 4. For this reason there is a chance your butterfly bush may not overwinter successfully. Be sure to apply a heavy mulch over the root area in late fall and hope for the best. Good luck!
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