Answer: Most hardy perennial plants will survive a freeze just fine although the foliage may be slightly damaged or discolored. Often the flower buds have not begun to form yet and thus flowering would not be damaged at all.
In general, it is better to leave them alone until later in the season when all danger of frost has passed, and then remove any unsightly foliage if necessary. Be careful at that time not to damage any emerging flower buds.
In the meantime, the tips may provide a little bit of protection to the remaining portion of the plant in case there is another freeze.
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