Answer: There are a few varieties of crepe myrtle that are root hardy into zone 6. Your zip code places you in zone 5B or the warmer part of zone 5. If you have a very sheltered, warm spot with full sun and well drained soil, you might have enough of a microclimate to grow them essentially as cut-back shrubs. This means they are killed back to the ground each winter, then regrow and bloom in the summer. With this type of situation, they never reach the size and stature of a tree like the ones we see in warmer regions. If you are willing to accept a "bush" then you could experiment, but if you really want a "crepe myrtle tree" then you will be very disappointed. Your local Penn State extension may be able to tell you if anyone in your local area is having success with any of the named varieties. That would be a good indication of what to try.
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