Alot of questions and I am not familiar with the clematises that you mention but there was a possibility that your Henryi didn't die. Sometimes young plants disappear the following season and may not emerge again for a year or even more - at least according to a number of people on the clematis forum. For my own (a "Prince Charles" that is going into its 4th year for me), it is a group 3 so for winter, I leave the vines on its support and in late February, I'll go out and cut it back to the first couple pair of buds. Often the rest of the vine has some buds trying to swell during late winter warm spells, but I still cut the whole thing back because it will inevitably engulf the support by bloom time. When/how often it is recommended to water during winter - that is mainly if it is dry (no rain or snow) and/or in my case where mine is on a covered balcony and happens to be against my bedroom wall and not along the rail to really get much natural water unless we have a Nor'easter (where I face NE and get the full brunt of those windy wet Atlantic coastal storms). One would water when the soil was dry and the temps were well above freezing - ie., in the 40° Fs or higher. In general, plants need less water during the winter when dormant, but they do appreciate some for their roots as the roots continue to grow in winter when the soil is not frozen. Yes, the containers can often freeze, but the bigger it is, the longer it would take to do so. For hardy perennials, this isn't so much of a problem as a detrimental cycle of freeze/thaw, which can burst the roots. So once it's frozen, it should hopefully stay that way and graduallly thaw. If you get snow, then that is a good insulator and you can put some mulch on top (I use pine needles on my clematis). Only thing you can do is try. You might have a mild winter that will allow a young plant to establish a more mature root system and gradually gain its fully hardiness in a container. I am finding that this is often the case with plants - they need time to gain that hardiness (even if planted in the ground and moreso in a container). The one other thing to look out for is the phenomena where containers often heat up faster than the ground, so sometimes this triggers your plants to wake up a little earlier than they should and then along comes a frost or freeze. Clematis buds are somewhat sensitive to sudden freezes if they are swollen or leafing. This was my clematis at the end of last June: The ridiculous below-normal temps makes me think it ain't gonna be ready to bloom earlier than normal like it did last year! Especially since it looked like this on 5/23/04: - and the stems are barely 2ft or so tall right now:

Plant them in the ground. Providing it's a variety that should be expected to be hardy where you are, they should winter over fine - same as the countless self-seeded clematis seedlings that I dig up every year from our yard to give away. This is a question that arises often, but just think about it - if seedlings of perennials were not just as hardy as the perennials themselves (not less hardy than mature plants,as people seem to believe), they simply would not have been able to survive in nature, would have they?

JPW, I personally don't like to attempt to overwinter clematis inside the house for the reasons you mentioned with roses above along with the fact that the plants tend to get very leggy unless you have a window that gets lots of direct sunshine. You said that last year when you attempted to overwinter them outside, that all except one died. How big are the pots your clematis are in? How did you attempt to overwinter them outside last year? Did you cluster the pots together in a sheltered location? Did you leave them sitting out in the open where they were exposed to the elements? You could attempt to cluster them together and place some sort of insulating material around the pots such as bales of straw or the like. Even if you had an unheated area where you could store the pots after they had been exposed to sub-freezing temps that took them into dormancy, that would be better as far as I am concerned than attempting to bring them inside the house. Do you have friends with uninsulated garages or even crawlspaces that could store the plants for you?

I have just joined this forum but have been gaining a ton of info for a no. of years.....has helped me become addicted a long time ago.......after having some clems planted because I needed to cover a fence my neighbors put up!! only asked what the climbing purple flowers were and said plant them. didn't know what I was getting into,[nor what kind were planted] I had been trying to find out how to overwinter some clems in large containers....last year I put some insulation around one in a wine barrel planter....it was thin silver insulation that I wrapped around about 3 or 4 times.[ the whole roll of insulation] I had bought as unmarked..turned out to be hagley hybrid...they came up this spring and did great...flowered nearly all summer....now I have 2 wooden planters that are about 16 inches by about 3 feet....last year I took them up and planted in the ground....then in spring replanted in planters....this year I have just wrapped them in the insulation... I'll see how they do... all of the ones I had planted in these containers had not made it the year before.[the first year in planters]. thanks to all for all your good info.....and now that I have decided I have no more space, Koi gardens comes up with a sale!!!!