Thanks so far, but I am not interested in white. I know the contrast would be great, but in my case the entire trellis is all bright white vinyl. So, I just don't think the white would "pop" as much. Anyway, I am open to suggestions. I'm staying with a Group 3, but really want something that's definitely going to make it to the top of the 8-10 foot side of the trellis every year after being cut back. Long bloom would be great as well. So, so far that's why I have come up with the three I listed. If something else fits the bill, please explain.

I should have added, but I was too lazy to type it all at the time, that not all group 2's die back to the ground every year. Many of the vines on The President and Multi Blue and a couple of others survived this winter. Nearly all the vines of Arctic Queen survived last year, at least to 2-3 feet, but didn't do as well this year. I don't know why that happened considering there was even vine survival on a couple of group 3's. Anyway, even though some of last year's vines survived, we had a cold, cloudy April this year, so the plants haven't grown very fast, but they did set buds. The first flush of flowers will be low on the plants. This is why we have to be careful of what we buy and where we put it because you just don't know what will happen each spring - Any clematis, which blooms May-June and again in September, such as HF Young for example, isn't the best choice for someone in the cold zones who is just starting out with clematis. Winter can kill the previous year's vines, and an early frost could crush the September flush. You wouldn't believe how many of these clematis are sold in our garden centers and nurseries every year. I have a few May-June, September bloomers. They are currently growing in predominant locations, and will be moved out into the perennial beds this year. I don't want to completely evict them from the garden, but they are taking up valuable space and some day might have to give up their place in the garden for hardier plants.

My Fireworks has been slow growing up to this point; it's been in the ground 3-4 years. Maybe someone else can speak about the size of Fireworks in their garden. The Jackmanii has viticella parentage, so it can get large, quickly. Some of us in the colder zones are experimenting with cutting back group 2's after the first flush, hoping to get a 2nd, but some of mine never stop blooming. Early tests seems to point to our growing season being too short to get rebloom on most(?) group 2's but people have had success. You should experiment in your own garden. Some of my group 2's are still blooming well. Don't cut back group 3's. By the time most of them have finished blooming, it will be close to fall. I don'think there is anything to gain, and the green vine and the interesting seedheads looks nicer than a bare arbor, but that is just my opinion. Although there isn't good information on how beneficial deadheading clematis is, it won't hurt and perhaps it will help produce more blooms. I prune my group 3's by half in late fall as soon as the plant is dormant, then do the final pruning in early spring.

Depending on the size of the pots, you could always dig a hole in the garden and sink the entire pot in the hole. The soil will serve as insulation and it will be as if the plants are truly planted in the ground. If the pots are easily moved, then you have several options. You could move the pots to a protected corner outside and pile leaves or bales of straws up around the pot to offer more insulation. You could leave the pots outside until the plants have gone dormant for the season and until it starts getting below freezing and staying that way for extended periods of time and then move the pots to an area where it will stay near but above freezing so that the clematis remain dormant the rest of the winter. This could be an unheated garage or even basement provided the basement is not heated. I personally would never try to keep a larger clematis actively growing over the winter since it is likely not get get enough light and start getting leggy and more prone to get infestations of various critters such as mites, aphids, etc. If you have a greenhouse or a solarium where there is plenty of light, then I would try to keep the plants actively growing and only then. JMHO, someone may have other ideas.