Right, so a local fellow is offering up the three title species, all of which are growing in the ground. Need a bit of advice from you lot about potting this up while it recovers, as all I'd do is plonk it down in a pot with some good soil and let it do its thing... I generally keep all of my bamboo potted, in full sun, and watered daily, but I'm guessing that's probably not the best idea with a freshly dug wad. On the plus side, I divided my Dendrocalamus Strictus tis Spring, and have each pot now putting out a new culm. Certainly hoping to get more than *one* out of each division, but at least I didn't kill it. Not bad for a first go of things!
I think you'll get by just fine here with common sense. Obviously the newly divided clumps will need some pampering while they recover from the trauma of being dug up and ripped apart and all that. So you'll want to keep them shaded (though still in bright indirect light) and misted and watered. If they're small enough -- or can be pruned to fit -- then an easy solution is to enclose them, pot and all, in a clear plastic bag, with the opening either tucked under the pot or closed with a twist-tie. Another really helpful thing is a one-time soaking with a weak solution of seaweed extract, or some equivalent product that provides a good dose of micronutrients without nitrogen which would just encourage foliage growth (which is not what you need just now). Bamboo pros, I think, advocate pruning the culms back by about 50 percent to prevent dessication due to trauma and loss of root mass. I've always just let the plants take care of that themselves, if necessary, by shedding leaves (or losing whole culms in desperate times). Never turn down a gift bamboo!
What kaspian said is what I've heard recommended and I can attest that we ordered in a lot of bamboo from a supplier and when it came it had clearly been field dug recently. The happiest plants had at least a foot of the original rhizome attachached. The most unhappy had almost none of the original rhizome attached and shed leaves like crazy and looked generally decrepit but none of them have died yet. Try to get as much of the main rhizome as you can beyond the clump or shoots own little roots that will still fit in the pot. Also if you're transporting them make sure you wrap the roots in wet newspaper then plastic bags so they don't suffere greatly (bamboo doesn't like to dry out completely at all when dug up this way) and wrap the culms in plastic and tape them up so the wind doesn't dry out and kill all the leaves when driving down the highway. There is some excellent info from a pro here: http://www.needmorebamboo.com/digging.html Scroll to the bottom section on that page and you will find out everything you need to know.