It's not "grafting" you want to do, it's "propagation" -- making new plants from cuttings or divisions. I posted a link to an older thread about this below.

It's usually divisions (that contain roots, at least one culm with leaves, and parts of rhizomes) that are used for propagation, although it sounds like it's possible to root Bambusa from cuttings.

Also, bamboo is not a tree. It's actually in the grass family. =)

Here is a link that might be useful: older GardenWeb thread on this

Hey thanks Alan - appreciate the lesson and the link. Going to check that out now.

shaun-
One other clarification. The bamboo culms you now have will never get bigger than they get during the season they come up. The plant as a whole will get bigger over time as new culms come up and they will be larger versions of what you now have until the plant reaches its maturity. At that point, new culms will reach the largest size that culms get for that particular species.

Easiest thing to do is take a few divisions, as propagating from cuttings can be very tricky. Different varieties propagate better at different times, some propagate better using branch cuttings, some better using whole culm burial, etc.

I don't have Malingensis in my collection, so I have no other info on propagating that variety.

Thanks everyone.