Hi, A/C is bad for any plants really, and the air will be drier than you realize for plants, however what I think did in your trees (if there's no green under the bark when you make a scratch on the trunk, they're goners) is the timing of your work. Spring, just before buds open, is when you should be doing all that pruning. Trees are in the process of going dormant now for winter and don't do well if stressed by cutting. I think we've all been there though, so try again next year. Fall and winter are not the time to do any work on trees except maybe light work on indoor tropicals. BTW, roots grown in water as yours are (tho' it won't matter to them at this point) are generally not as strong as those in soil, and when you go to pot them up, don't always do very well as a result.

Well depends on the Redwood you're using. It could be Giant Sequoia, Dawn Redwood, or Coast Redwood you're referring to. Personally Giant Sequoias foliage just does not work with bonsai. Dawn Redwood and Coast Redwood both back bud like crazy, and grow very fast. I'll get some pics up of a Dawn I've been working with, but it doesn't have much done to it in the way of styling.

Just at a guess, giant sequoias might do better than coast redwoods in a climate with cold winters. After all, they grow in the Sierras. Coast redwoods once had a much larger range than they do now. These days they are happiest in the fog belt of the coast, cool temperatures and damp air. I honestly don't know how flexible they are about conditions. I was surprised to see them at the Arnold Arboretum in Boston. Or were those sequoias? I thought I saw both. The third member of this family, dawn redwoods are wonderful trees. Please be aware though that they are deciduous. Sometimes this comes as a shock to people who thought that all conifers were evergreen. They are one of the exceptions. I am blessed to have four coast redwoods growing in my yard, sixty or so years old. No credit to me (they were planted before I was born), but I do feel fortunate to have them in my care. There is something wonderfully inspiring about these magnificent living things. Rosefolly

I'd agree with smivies and kentrees that they probably won't be very happy at the OP's location, or in much of the eastern US. See the last 2 posts by sam_md in this thread: http://forums2.gardenweb.com/discussions/1736468/baby-giant-sequoia-in-winter?n=30 The tree pictured in the link below is growing near the Lake Michigan shoreline, and it seems to be doing well. It apparently benefits from the lake effect snows (and moderated temps) at that location. 95' tall, planted in 1948: http://midmichigannatureandscience.blogspot.com/2015/08/field-trip-michigans-largest-giant.html