Hi Annie, I've got columbines almost ready to bloom here. These are very hardy and come back reliably every year. I would think that you are safe in starting to harden them off now.

Not sure about the rest though.

Ang

I haven't noticed any of my daturas (Angel Trumpets) sprouting yet outside, so I would think it's still a bit early for those.

The Moon Vine and cannas, I would wait until after any chance of frost is done. I'm not sure about the cypress vine, as this is the first year for me with them too. Ang is probably right about the columbines too.

Best to play it safe, unless you want to be covering things if frost threatens.

Laurie

I already hardened off and then planted out my columbines. They have survived -4 once and -2 a couple more times. No problems. For everything else, I would say wait.

My plants have been outside for 3 weeks or more. I have 2 of those mini greenhouses and I have them set on the south side of my house. Some of them are left outside at night without the greenhouse. They get put in when there is a threat of frost only. This year my blooming lilies in pots that have stayed outside in this spot through the hard frosts. Right by your house you have a micro-climate. I've been leaving my plants outside for years like this.(This is the first year with the greenhouses.) The odd touchier plants may be bitten by frost a bit but only when the tempature dips quite low. I now only grow plants that tolerate a bit of frost. Really touchy plants like begonia's, I don't bother planting. (Even though I truly love them.) Mother Nature has played tricks on me way to many times.
Shelley

Well, I brought a few things outside on the deck yesterday to start hardening off. But they will be brought in at night. (species lilies, hosta, ligularia, osteos 6 pak and the the two osteo planters, nanking cherry and the two roses) (Also the 6 fuchsia baskets are out everyday and back in house at night)

Today I plan on moving the petunias to the greenhouse and leaving them there with a heater at night. Petunias are pretty tough and if I lose them they are easy and cheap to replace. Hmmmmm I am also thinking about moving the rudbeckias and gaillardias out as well. Not the real tenders though.

Last approx. frost date here is June 6th.

Sierra