You should not have any trouble with nigra in DC. I also have clay soil and I have no problem with them in New Jersey (zone 7). In the very coldest winters, some culms may suffer some burning but the plant will recuperate in the spring and summer. Go for it!

The main reason I'm asking is that I really haven't seen any black bamboo in this area. I see a lot of bamboo in this area but have not seen any grove of Nigra anywhere. I'm thinking there may be a reason for this. If anyone has a large grove in the area that they want to trim, I can buy some. I can dig it up myself for a good headstart instead of buying it from the nursery.

We live in Marshall, VA and we have been growing it for years. No problems even when it gets a coating of ice on it. Even if some of the culms die, there is still plenty under ground to grow new culms.

I've had P. Nigra (Henon) since 2000, it barely spreads, but if we don't get down to 0 in the winter, it does great the next year. But if it goes below zero, it dies to the ground, and then comes back wimpily next year. We have really hard clay soil, but doesn't faze it too much. It's not spreading real fast, but we are zone 6a after all. It doesn't get much shelter because we live on a ridge. HTH! :)

I planted 4 plants on our roof terrace in Washington DC last October in 2 large planters. The plants are healthy and beginning to spread.