From those pics I would guess that it is a runner, but even if it is, there's no need to panic.

Can you post a picture of the whole plant, or the base of the plant?

How far apart are the exisitng culms?

Are there any grooves on alternating sides of the internodes?

Kt

If you don't see a clump, it's not a clumper.

Thanks. I can't get a photo of the whole plant because it's not in my yard, and behind an ivy-covered fence. (The top of it is in the second photo but that's not really informative.) It's close to the fence so judging from my own clumping plants, the culms in my yard aren't so far away as to be out of the clump if that makes any sense. It could be a gradual spreading clump. From what is on my side, I'm guessing the culms are 3-5 inches apart.

There are grooves...
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If I dig it up, should its growth style be apparent from the root structure?

Yes, looking at the rhizomes would help determine between a clumper and a runner.

I believe that you have a runner, judging by your last picture.

Some runners spread slowly and even more slowly in colder areas.

Nice looking bamboo.

Kt

Oh dear. Is this Ph. aureus?

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Yes, that would be my guess. P. aurea aka Fishpole bamboo.

It is very common around here. Groves as large as 2 to 3 acres are not uncommon.

Kt

If it is aurea, then it should be a relatively small, but very rampant runner so if you don't want it to take over, I would suggest going with a different species.

If you are in zone 10, you might as well go for the dendrocalamus giant bamboos or the bambusa tropical giants for a real bamboo look.

Yes, its definitely a runner. Usually the older canes are yellow. But the dead give away is the very sharp edged sulcus or groove running along the nodes. Clumpers do that but with softer edges. I'm in 9b and i've seen that p. aurea take over. I like stevelau's idea. Just battle it with some big timber. I like dendro but if you're on a budget plant bambusa vulgaris. It's an open clumper with strong roots and one of the easiest to propagate. If money is not an issue, then look at Parker Giant or bambusa dolichoclada. They're awesome.

Steve, it's sneaking in--I didn't choose it! I was just wondering if I should recycle it. :) But I won't transplant the bit I dug up. I wonder why it took so long to get over here. Maybe it recently broke through a barrier. It's in a very tidy and well-maintained yard.

We do have a nice Bambusa ventricosa and a B. multiplex and they are perfectly well behaved. I used to keep Fargesia spp. in zone 6--I like things to grow slowly so I can keep up. I'll look into some of the bigger species when we "do" the backyard. And I'll stick with the clumpers.

I don't imagine this bamboo can be nearly as bad as English ivy or wild blackberries can it? Can I just stomp on it when it pops up? Can we eat it? Focus focus...

It seems pretty shallow rooted. Would a narrow trench along the fence line keep it out? It's getting pretty close to a nectarine and a tamarisk and once it gets there I think it'll be impossible to remove. It's just a small incursion right now and I could probably dig it all out in 20 minutes. (Yes, the previous owners actually planted a nectarine next to a tamarisk and a fence. I think the tam could beat the aureus but the nectarine is a wimp.)

I'm impressed with the strength of those culms. Wow do they not bend! I guess that's what the groove gets you. It's very pronounced.

Thanks all!

It's definitely Ph. aurea. You can stomp on the new shoots, but that will not stop the root structure from spreading throughout you yard. If you want to control it, it would be best to: 1) dig along the fence line and put in barrier, and 2) dig up all the rhizomes that have already made it into your yard.

P. aurea grows to 30 feet in height here and about 2 inches in diameter. It can be aggressive under good conditions, but also can be controlled.

One other way to control it would be to use a sharpshooter shovel or the like and cut a path along the fence once or twice a year, to severe the encroaching rhizomes. If anything pops up on your side of the cut, simply break it off.

Kt

Thanks guys.

At least it's pretty. :)

BTW, it's not your responsibility to maintain or apply a barrier to control it.

I would suggest letting your neighbor know about it and have them put down a barrier because their plant is invading your property. The more aggressive runners such as aurea usually don't grow much deeper than 2-8 inches when they come in initially, but don't be surprised to find them getting down to about 2ft deep when you keep trying to stop them from crossing.

You can probably get a few species of tropical clumping bamboo either locally or on the bambooweb forums that I posted. There should be people there who are willing to spare some of their bamboo at a good price.

Here is a link that might be useful: bambooweb forum