I recently purchased this plant commonly called japanese knotweed. I've been doing research and found that some varieties are considered invasive. Has anyone had experience with this plant. It is very beautiful but I want to be sure before I plant it. Thanks for any info you can give me.

Yes, it is invasive if not kept contained. This is what I found about it:

http://www.cabi.org/BIOSCIENCE/japanese_knotweed_alliance.htm

I looked it up, as I've never heard of the name before, but as soon as I'd seen a picture of it, I realize I am well familiar with this plant. It has been growing at the side of the house and barn at my childhood home ever since I can remember. It grew like a little forest! Mind you, as a child we had loads of fun in those 'forests'. We always called it bamboo, tho I knew it wasn't real bamboo. Now I know it's real name. In recent years, my mother has tried to get rid of it by hacking it down every spring, and each time it sprouted, and it's worked for the most part, but stragglers are now invading inside of the garage and the barn with shoots popping through the concrete...any crack it can find, and there it is. So yes, I'd say it's invasive. As for containment, I'd plant it in a container, making sure there were no holes where the rhizomes could escape from and keep a close eye on it. The website I found has alot of good information on it, and it's a good read. Good Luck.

Thanks for the website. It gave good information. Your suggestion re container is a good one and I may try it in a very heavy one. The tag says it grows 12"/18" in height and 18"/24" spread.I checked other sites as well and found some information on the plant I purchased which is the "compacta" variety. The information on this variety states that it is better behaved that the one that is terribly invasive. One site states it is not invasive,however, I would like to know if anyone has experience with "compacta" especially in zone 3 or 4,to know whether it is truly non- invasive. I appreciate any information. I really like the look of it but I have planted other species that have been difficult to get out of my garden. The fact that it can crack foundations and walls scares me. Thanks.