That is highly unusual, and the fact that the canes were dried makes it even more perplexing. Usually the only bamboo that can be started from culm (cane) cuttings are certain tropical species, and you do tht in a special way with freshly pruned culms. Now it's possible that the stakes you bought came from SE Asia where this type of bamboo is common, but when they're dried they're essentially dead. I don't know what to say. Could you post a picture?

Are you sure it is actually bamboo? Last year I went to a flea market and a person there was selling "bamboo" stakes that were actually Japanese Knotweed and Japanese Knotweed can propagate from small pieces if they are not completely dead.

Bill

I'm not sure this is bamboo, I'm looking for some educated imput. These were found in a bed with castor bean and elephant ears. I kept all the seed pods cut off so I know it's not castor bean. There are some tree roots from a plant that was there (before we bought this house) but the growth comes off a big root, not a stand alone plant. Anything I find growing in my beds gets pulled out, not cut off. I can't think of anything else that could be there. It doesn't seem possible that a bamboo stake could start growing. Here is a link to some photos
http://www.flickr.com/photos/7464701@N02/
Does bamboo even have roots like this?

Here is a link that might be useful: bamboo?

Doesn't look like bamboo to me.

ekoboat-
It's not bamboo. Not only doesn't it look like bamboo, bamboo has no seed pods, and it doesn't have the pith that shows in your photo. That looks like some woody plant or weed to me.