They're tender perennials, but I don't know how long they can actually live. To winter over, you can take cuttings. Or you can try to bring in the whole plant, but that might be hard on them if they've grown a great deal over the summer. I planted mine in July this year so they're small and just starting to bloom. So I'll bring in the entire planter and grow them under the brightest light I have. Maureen

I don't really know from a factual point of view.

I have some 'wave' petunias in hanging baskets though (and other petunias in other places I don't pay much attention to).

The wife went ahead and snipped the petunias off at soil level as soon as the Wisconsin freezes killed the plants.

A month later and many freezing nights and days later there is a small amount of green sprouting from the roots in those hanging baskets.

All this tells me is that given a little warmth these petunias aren't ready to give up the ghost yet.

I would say petunias are good for *at least* 2 years if overwintered.

One caveat is that petunias tend to look like hell by the end of the season. From what I understand this is because petunias only flower at the ends of their stems and if not pruned back this results in an empty spot in the middle of the planting.

No worries though, just mow them down once frost knocks them back and let them regrow in spring if you can overwinter them indoors.

Petunia x atkinsiana, the common garden petunia derived from the nightscented whiteflowered annual P. axillaris and the violet dayblooming P. integrifolia. As the parent species are annual the older diploid hybrids also are. But as so often in culture plants as in neophytes they change there habits, often with ploidie levels. Modern Petunias can be grown as perennials.