Can you please id this weed? I like to call it "The Weed from Hell". My backyard backs up to a conservation area. And i see this weed growing throughtout it, and its made its way into my yard. Its very thorny and it grows in a row. Im not sure how tall it can get but the tallest I see is about 5ft. From the root of one it sends another shoot underground about a ft or less, and another one pops-up. And it continously shoots up more and more. I found this out becuz I dug outta part of the trail. Luckly it only shoots out one from each weed formed. I have a trail of them going through my yard about 20ft long. The lawn mowers keeps them at grass height. If you try to pull it outta the ground it breaks off. Ive tried "Image" brand weed killer and that did nothing. I havent tried round-up becuz i had a bad accident with it. I sprayed an area and it rained later that day. I caused it to spread and kill a bunch of other stuff. My dad said it looks like some kinda of wild berry. Any ideas on how to get rid of this thing or atleast keep it under control.

Thanks

Here's some links to the pics:

http://70.119.163.54:6969/weed01.jpg

http://70.119.163.54:6969/weed02.jpg

http://70.119.163.54:6969/weed03.jpg

http://70.119.163.54:6969/weed04.jpg

Image link: