The word bamboo does not come from Latin for amazing, but it should. A mature stalk of this enormous member of the grass family can leap into the sky at a rate of up to 2 feet a day. And the stately stalks, called culms, are strong enough to serve as building material, yet the bulk of the plant is its root structure. If you think of backyard bamboo (Fargesia spp.) as a large tree, the culms are the leaves but the trunk and branches are thick roots, called rhizomes. You can propagate bamboo by taking rhizome cuttings with leafy shoots attached.
Dig a trench at least 4 inches deep in your backyard in an area with well-draining, fertile soil. Select a spot that is protected from the sun during the hottest part of day. The length of the trench depends on how many bamboo cuttings you intend to plant there.
Dig up a young, established bamboo plant between January and April. Select a plant on the outside of a clump or grouping. Remove the soil from around the plant's rhizome with your fingers, taking care not to damage it. Inspect the rhizome to make sure it is healthy and full of buds, not dark or spotted.
Wipe a sharp garden knife with a rag soaked in denatured alcohol. Slice off a section of the rhizome with the knife, together with a piece of leafy shoot growing above ground, if possible. Lift the severed piece from beneath, leaving as much soil as possible attached to the outside of the cutting.
Place the cutting in the trench, leaf tips upward, and pat in 4 inches of soil over the rhizome. Water slowly and thoroughly after planting. Keep the soil moist but not wet for a month or two until new shoots emerge.