Here are more pics, notice the speckled red dots on the stem on the 2nd and 3rd picture. The first picture is of it when it has just sprouted out of the ground. It has a brownish/reddish hue in the beginning of the growth cycle and they are deep rooted.

Oh dear! I don't like what I have been reading so far. Thank you for solving this mystery.

Bookwoman (or anyone else reading this) I did some more research on this and it seems that the common eradication method is to use Roundup. I would like to avoid chemicals so I am hoping that cutting the weeds, say, about every 2 weeks, would weaken it. What would you guys suggest for someone like me who wants to avoid chemicals.

Nikki, I also don't like to use chemicals, but every two weeks won't do much to this plant. I was tempted to use Roundup, but my knotweed was in a bed with some
nice mature plantings and I didn't want to risk harming them. The way I got rid of my small stand was to dig up as much as I could of the root masses, and then diligently - meaning nearly every day - dig and pull up any new shoots that appeared. I did this daily treatment for two summers in a row, and then less often the third summer. So far this spring I've only seen two puny shoots, but I know I have to keep on top of it or it'll once again take over.

That said, this is a *very* nasty weed, and depending on how much of it you've got, you may have to resort to Roundup. In any event, I wish you good luck!

"What would you guys suggest for someone like me who wants to avoid chemicals."

Move!! Seriously, this is an extremely difficult plant to eradicate, even with strong herbicides. This publication is only one of dozens that explains how to control JK and most will indicate a similar approach - use a combination of manual, cultural and chemical removal and exercise extreme diligence. You must use repeated attempts during the growing season of every 10-14 days to effect anything close to eradication.

Good luck - you'll need it!!

Thanks Bookworm and gardengal! Unfortunately, I can't afford to move nor do I want to. I think I will be pulling every few days to weaken them, if it takes a few years then so be it. Again, thanks you guys!

Please read widely on this horrendous plant. Pulling will get you nowhere. If you really don't want to use herbicides (and this is the only plant I have ever used herbicide on) you need to dig, and dig deep and wide. Do not compost the plant or even put it in the trash. Burn it on site very carefully. Do not allow any piece to escape.

If you put paper under the weed and spray over the paper you limit how much Round-up reaches your soil.

Not a concern of mine, but I understand.

No need to spray. Paint it on.

Thank you all for your advice! I will carefully consider my options here. The problem is that my backyard abuts my neighbor's yard and his yard is BURSTING with these weeds and he doesn't necessarily have a green thumb. I told him about the weed, since we have been wondering for years what it was and he wants to get rid of it but I am not sure if he has the tenacity that it takes to keep at it month after month. So even if I successfully eradicate it in my yard, it will keep coming back because it has free reign in his yard. *Sigh*

Check your local by-laws. Over here it is an offence to allow JK to get into a neighbour's property. I'm not suggesting getting heavy but a hint might encourage him to do something about it.