Good question! I might have to try myself :D

Supposedly these are hardy to zone 8b, but have read even folks in this zone have had trouble getting them to survive their winters. I myself am having trouble getting them to do anything at all! I did mine the wintersow method way and have had them in the ground for quite awhile and just now they are starting to gain some growth...a big 2.5-3" tall LOL!!! Maybe with these 90's-100's in the forcast and some serious watering they might make something of themselves...hmm?
Believe I will try wintering one over...can't hurt to try, right?

Vera

They didn't overwinter for me but I didn't actually do anything to protect them - I treat them as an annual. They put out hundreds of seeds so I decided to save some and direct sow them. That method works great.

The plants grow really fast and sowing the seeds in late winter or early spring is easier, to me, than trying to overwinter a mature plant. Another thing, too, is that the birds will strip the seeds from a plant in the landscape if you aren't careful....something to keep in mind if you decide to collect seed for direct sowing next year.

Good Luck~
Renee

This should be treated as an annual. It does seem to come true from seed, and you get vigorous young plants that way instead of whatever tired specimen might barely survive indoors over the winter.