What are the leaves like? Tough? Tender? How does the veining run? Are the leaves on petioles or do they grow right from the stalk? How do the new leaves emerge? Did you repot it & know what the roots look like?

I haven't noticed any berries on them, I'll have to look closer. They seem to spread very fast, every plant has a Y branch as it comes out of the ground, many can be pulled out but not all. What worries me is how much I found along the back perimeter of the yard, it seems to have spread quite a bit when I wasn't looking.

Thanks for your responses. Sorry it took me a while to follow up. In the original post I used the word "rootstock" perhaps too casually. What I meant is that there's a thick, woody log-looking vine along the ground, from which the canes are sprouting. Two of those canes are green, two are woody. All are sprouting out long vines that are green, and covered with leaves at the end. Bear in mind that they are long and leggy like this because before I cleared the way they had been both covered by brambles and climbing up into a tree. One more possibly useful piece of information is that this thick stock is planted next to an active climber that's very common in my area, one with countless little (2 1/2-inch diameter), light pink roses with many petals. Can't remember the name but I would recognize it. I'll post the a photo of the base/rootstock (?) here, and in two more posts a photo of the leaves and of the whole deal. (The site will allow me to post only one photo at a time.) Would appreciate your advice after seeing these images.

Trust me, I've grown over 100 species of bamboo and am familiar with hundreds more, and that's not bamboo. It's true that bambooS don't flower frequently, but when they do they don't produce tassels. Just because that plant doesn't produce flowers doesn't mean it's bamboo. Many other grasses have canes that sort of look like the culms on bamboo. However, I bet if you go over and take a close look at that plant you'll see the leaves originating directly from the cane, whereas bamboo leaves don't do that: they grow on branches that are attached to the culm. In addition, i'm guessing that the plant you pictured dies back during the winter, and grows back from the ground up each year. And it doesn't leave woody, erect poles like you remember from fishing as a kid. Correct? I can't tell you for sure what the plant is because I'm not an expert on other types of grasses. it's some type of giant reed/grass, and I understand why you might think it looks like bamboo. if you decide to grow it, just remember that a lot of the reeds can be quite invasive, so you'll have to do some work to keep it under control. Maybe you should post your pictures in the Ornamental Grasses forum here on GardenWeb to get more specific ID and information about this plant. As for fishing pole bamboo,you're probably thinking of golden bamboo (Ph. aurea): Golden bamboo