Sounds like shock from dividing and transplanting. You will lose some of the culms whenever you divide a pot of bamboo. I have a 5 gallon pot of Textilis that is sitting inside of a larger pot of water that I keep about 3 to 4 inches deep. As you said, you do not want the rootball completely submerged in the water. I do this since the plant cannot make it a full day here without extra water, and would die before I get home from work to water it. It has been growing this way for over 3 years now. I would guess no more than 1/2 of the roots/shizomes should be kept underwater, but less would be better from my experience. Kt

Banana Babysitter....you sound like a very good friend, that is being taken advantage of big time! I know this isnt the advise you wanted. She dumps some huge banana 'trees' in huge pots on you, and doesn't tell you when she will take them back? She is paying you how much for taking care of them, for the water, fertilizer,new pots, soil etc... they sound like they are getting big and need bigger pots,more soil,etc. And they are going to go back into a small apartment...when? They don't fit now in the pots they are in now, and she cant handle them?...right? How is she going to handle bigger trees? They aren't going to grow in reverse and shrink. So she won't be able to take them back. It sounds like she is taking advantage of your friendship. I mean being a friend is one thing, taking advantage of a friend is another thing. Sure they can live in pots for a long time, certain 'ornamental' ones can live in pots all their lives inside, but fruit bearing ones, and these sound like fruit bearing ones, will just be unhappy and not look good and can grow so many pups in the soil,they can break clay pots easily! And split plastic pots in half. They need to be outside in the ground. Call and tell her to come get her babies, or they go to the dump or a community garden, if you have one near you. Or at least ask when is she coming to get them? As you see they grow inside, sure, but as you also see, they arent to happy, they dont look to good, and to many pups are starting in the pots? Those will crack a pot very easily, so can just the roots! They can grow a long time inside,if you had ornamental varieties, thats one thing, but these sound like fruit type, and they need room to grow and full sun and tons of water, and fertilizer. They wont go into a small apartment. You have a lot of patience.

Brian- My potted bamboo have very little rhizome showing aboveground, and they have a pretty decent belowground root mass if they have been in the pot for 6-12 months. When I'm doing divisions of bamboo from in-ground groves, I tend to use a root pruning saw, a corded SawzAll if I'm anywhere near electicity, and a lopper, depending on what I encounter. Typically, I try to get through the rhizomes in the gentlest way I can because I think it induces less shock. I have used an axe, but don't find it very efficient and I don't like the results. I'm just getting into propagation from rhizomes because my bamboo are sending out a lot of nice runners in my new location.

I got interested in growing dahlias in pots a couple of years ago when we stopped to eat at a restaurant with the most gorgeous flowers. Some of them were as tall as the gutters on the roof. Then I realized they were ALL grown in pots, and that blew my mind (and all were dahlias!). I started with 4 plants last year but wasn't brave enough to grow them completely in pots. This year I plan to do most of them in pots because I've upped the number to 25 and don't have the space to plant them all in ground. I also think from what I've read over at www.cubits.org/dahlias that they do just as well in pots. It certainly would be a lot easier to dig them up in the fall after that first killing frost. If it was an especially early frost, you might be able to move favorites to a sheltered location and get a few more weeks of flowers. The idea of dividing them in my potting area is much more attractive than the thought of digging them out of cold wet soil, as I did last fall. And I like vikingcraftsman's idea of using them as a screen!