If the stems are ok, then they'll put out new leaves. They might be a bit later flowering then they would have if they hadn't been hit by frost because the plants will have to redirect some of their energy into producing the new leaves, but they will be fine.

Don't beat yourself up about it! It was very hard for me to avoid the temptation and plant things out early too. We had such an early start to spring that a lot of people jumped the gun :-) I had a bad experience several years ago and lost a bunch of seedlings, so I'm overly cautious now!

BP

Bev, if it's any consolation, I was shocked to discover a dahlia growing in my garden. It had overwintered outdoors! These things are quite the survivor.

This is my year growing Dahlias, so I don't know how much abuse the young seedlings can take. I'm keeping an eye on them. I have more seed, so I can always start again.

re: overwintering surprises-- I had a couple of snapdragons survive last winter. Also, a Euphorbia called "Silver Fog" that I rescued last October from a pot in my mother-in-law's yard.

why don't you take a shape a cold frame out of a pop bottle and put it over your tender perennials? I did that with my verbena (being that this was teh first time ever I got to grow them and I didn't want to lose them)

Interestingly my basils have survived well outdoors.

That would have been a good idea. You know, I was just impatient. The dahlias were busting out of their pots and they'd been spending nights outside at near-zero temperatures for a week. So I thought they were ready. So I planted them and promptly forgot about them. The garden is so big and I have so many plants-- I just need a better brain!