It would be helpful if you could post a picture of the older culms. However, the kind of zig-zagging you describe is pretty specific to Phyllostachys aureosulcata, a commonly grown bamboo also know as Yellow groove. Is this a green bamboo -- perhaps turning to yellow-tan after a while -- with a yellow sulcus (groove)? Take a look at the pictures of the culms in the link below and tell me what you think.

Here is a link that might be useful: Ph. aureosulcata pix

Here is a picture of some of the mature culms. I thought it might be yellow groove but it didn't seem to fit with a lot of the pictures I've seen.

Mature bamboo culms can vary in appearance based on exposure to sunlight, which is why photos can be confusing for some bamboo. I have a number of green bamboo whose culms turn yellow-tan after long enough exposure. That photo looks like Yellow groove.

Excellent! Thank you so much! I feel much better now that someone else with more experience thinks the same way I do. This is my first experience with Bamboo. I think I've got another variety as well that only gets about 1.5 feet tall but it seems to thrive everywhere and is easily controlled with a lawn mower and a funny look.

Well, if you can post some pictures of the other one, maybe we can figure something out.