Answer: You are right -- butterfly bushes (Buddleias) are not biennial. Sounds to me like your butterfly bush barely survived the winter. In your area they should be heavily mulched after the ground freezes to protect the roots. Don't cut them back until late spring when you begin to see the leaves budding out. Then you can cut them back to about 8 inches, or you can just cut back what is dead, giving the longer branches a head start on growth.
They are not demanding plants, but need full sun and prefer a rich well-drained soil. They are wonderful shrubs that can grow to 6' in a season! They attract many butterflies, hummingbirds, and hummingbird moths. If your first attempt at a buddleia didn't work, don't give up! They are definitely worth a second try!
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