I dunno--maybe it has something to do with the region you live in, but in Zone 6 Kansas, Sweet Autumn Clematis is a weed--self-seeds prolifically and grows everywhere you don't want it. I swear I get hundreds of "volunteers" popping up all over my backyard every year. As pretty as the bloom can be, I hate this aggressive spreader so much that I cant even enjoy its bloom for more than a minute or two. Kate

I think the term "invasive" gets thrown about too much without a good understanding of what it means. I know which forum and thread you were referring to and few of the plants discussed are truly invasive - that is, able to spread at will, usually by seed, and colonize natural areas to the detriment of native plant populations. Aggressive is another feature altogether and is typically used to describe garden plants that grow rampantly, spread easily or are difficult to eradicate once established in your garden, but do not pose a threat to natural habitats. I'd describe SAC as an aggressive vine in that it grows rapidly and is big. Allowing insufficient space for it in a small garden could pose problems :-) And while it may generate a few seedlings (mine never has), it certainly cannot be considered invasive in the correct use of that term.

I was a warm zone SAC grower (zone 7) and it did seed all over. It was a prolific grower, would be cut to the ground each year, and the next season it would throw out 30' of regrowth. The biggest problem you'll have in a colder zone is it will potentially (100% guarantee it will) flop over onto your neighbor's side of the fence and you'll run the risk of having it hacked down. There are quite a few threads on Sweet Autumn Clematis on the Clematis forum, as well as the Vines Forum - check them out. And from what I can remember, while cooler zone growers marvel at its luxuriant growth, they don't find it to be freely self-seeding.

Well, I've spent a fair amount of time fighting honesuckle and multiflora rose to keep it out of the woods on properties I've worked at. Didn't realize until I Googled it that the native wild clematis, VB and Sweet Autumn Clematis were different, and that the non native one was invasive. It's the smelly one I want. The wild clematis is not showy enough to waste space on it in my tiny, tiny, tiny urban downtown row house yard. I don't feel there's much danger of my stuff invading a pristine natural area, the best luck a seed from my yard would have is to land on some vacant urban corner. I haven't read anything about the clematis being a big problem around here, but maybe that's because it is not very commonly grown or sold in nurseries. I don't mind cutting back the upper foliage, to keep it trained along the fence. My neighbors have a grape vine trellis that they have to keep after, but the roots don't wander, just the tops. But after that rose experience, I just don't want something with root suckers, because then I have to go into my neighbors yard to pull the stuff up, and it risks disrupting things, in my yard and hers. I don't want to accidentally uproot her tomatoes or something like that. Maybe I should go with a regular clematis. I sure do LOVE, LOVE the smell of the Sweet Autumn Clematis, and the flowers are pretty too. It smells like baby powder. I have such a tiny yard, I can never decide what to plant, because I am torn between wanting stuff to eat, smell and look pretty. I had to tear out my beloved crab apple which has all three qualities, because it was overrun with rust. I didn't treat it at first because the Cooperative Extension folks said it was just "cosmetic." But eventually the whole thing became infected and distorted and covered with the stuff. And I realized that the soil where all the leaves fell would now be infected for years to come. I finally put the poor thing out of its misery. Now there's a huge hole in my garden and I can't decide what to put there. So far I am replacing the tree with a red ninebark, but I don't know about along the fence behind it and on either side.