KG,

I suggest you contact the Missouri Botanical Garden with your questions. They are pretty expert about plants. Incidentally, it is is a great place to visit, volunteer, etc.

ZM

Ah, well, I'm not an expert but can only tell you if it's tropical at my house it comes inside for the winter. Not unusual to get down to 0 degrees or a bit below for a couple of weeks a winter.

The hardy hibiscus... well, I'm not sure how fast a plant can learn or unlearn what it's known all its life, but hardy hibiscus is grown around here; they stay outside and go dormant when the freezes come, and the plants come back in the spring. Hopefully yours will know to do that, but again I'm not sure about it. If you have a lot, you can always bring in some, and leave some outside to test the response.

I'm not wise in the ways of angel trumpets so can't help you there, but again would hope if a plant is genetically good to zone 5/6 it would know what to do in the event of a climate change. If not, bring it in and perhaps dedicate a west- or south-facing window to these plants.

I hope the move works out very well for you. Snow can be fun. :]

I second the advice to contact Missouri Botanical Garden here. (Sometimes locals call it MOBOT, which I think is hilarious.) They have people literally sitting there waiting to answer your questions, and it makes for a wonderful afternoon for anyone, especially those of us who are plant geeks and look at garden forums....

Another thing that works to winter some plants (I don't know about your specific ones) is to cover them completely with a mulch, like straw or chopped leaves or something. This kind of insulates plants that are "iffy" for weathering the extreme cold. This would not work for plants that can't tolerate any of the cold, just for some of the ones kind of on the border. And now that I wrote this, I'm not sure how CONTAINERS would do b/c they're above ground anyway. Hmmm. But that's just my experience.