The waves are a seed variety, so unless there are other petunias around for them to cross pollinate with them they should come back true. Freezing seeds overwinter is never a bad idea, so if you have space I would put them in. I would love to overwinter my Proven Winner petunias, but will likely end up with a big bug problem. I do cuttings from my Geraniums every year and they were awesome this year.
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