Answer: Butterfly bushes are grown as so-called cut back shrubs in cold winter areas; this means they often die back to the roots and then regrow every summer. They begin to bud and leaf out in mid spring. At that point you would trim back all of the winter damaged stems or simply cut it back to about twelve inches tall. They bloom on new wood so they will bloom fine regardless of how much is cut off in the spring. Your local garden center or county extension should be able to tell you approximately when to expect them to show signs of life in your neighborhood.
These plants are generally considered reliably hardy in zone 6 and some varieties are hardy into zone 5. They will survive better in these colder areas if grown in a well drained soil and heavily mulched for the winter. Your zip code places you in zone 5A, the coldest part of zone 5. Depending on the microclimate where you garden it might actually be as cold as zone 4. So although I would encourage you to be patient, I am not sure exactly what to expect. I hope they came through for you but some gardeners like them well enough that they are willing to replace them each spring.
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