Answer: Butterfly Bush, also known as Buddleia davidii, blooms on new growth. Therefore, stems should be pruned back in early spring to encourage large, lush flower spikes. I always prune back my Butterfly Bush on St. Patrick's Day to about 6-10". Seed isn't always viable but you can propagate your plant by dividing it in the spring, cutting the root mass into sections, each with several stems attached.
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