Posted: 09/11/2012 at 21:25
Those photos are very interesting.
At first sight the leaves do look very much like the dreaded Sasa.
But to my mind, those stems (culms) do NOT look like Sasa. Sasa stems tend to be slimmer and more bendy and do not tend to branch. Yours look a lot more like proper bamboo canes.
So I'm not sure that yours is.
You may be OK, but it needs watching.
The way that invasive bamboos spread is by thick underground roots, which are just beneath the surface of the soil. If a bamboo is non-invasive clump-forming, then it will not attempt to put out long roots near the surface.
So the best thing is just to see what's beneath the surface of the soil. Take a few spots about a foot away from the plant, and scrape down about an inch, and see whether there are any long exploratory roots radiating out from the plant. The absence of surface roots now doesn't mean that the plant might not put some out when it grows more. Just keep an eye out for any, now, and in the furture.
Or was the shoot that you got, from the parent plant, coming up from a long root just beneath the surface that had been sent out by the parent plant.
It's only a little plant, just keep an eye on it.
the darker looking shoot is new growth, which came up from the base of the original shoot, and the stem of the original shoot is very rigid (garden cane like) for such a small shoot (0.5cm thick).
As yet i havent been able to identify any roots spreading under the surface, so i think i'll be safe, but i'll keep an eye on it.
How far beneath the surface would invasive roots be if was spreading as such?