To stop bamboo spreading, you need to control its underground stems, called rhizomes. The three reliable options are to install a rhizome barrier, to sever escaping rhizomes with a spade once a year, or to grow bamboo in a container. The permanent, no effort fix is simply to choose a clumping bamboo, which does not run in the first place.
Only running bamboos such as Phyllostachys spread. If you are not sure which you have, read our guide on whether bamboo is invasive first.
Install a rhizome barrier
A rhizome barrier is a thick, rigid plastic membrane sunk vertically into the ground around the planting area, to a depth of around 60cm. Angle the top slightly outwards and leave a couple of centimetres proud of the soil, so any rhizomes that reach it are deflected upwards where you can see and cut them. This is the best solution for an established running bamboo you want to keep.
Root prune once a year
If there is no barrier, you can contain a clump by severing the spreading rhizomes each year. In autumn or early spring, push a sharp spade vertically into the soil in a ring around the clump to cut through any rhizomes trying to escape, then dig out and remove the severed sections. It takes some effort but keeps a running bamboo in bounds.
Grow it in a container
Running bamboo grown in a large, solid pot cannot escape at all. Use a strong container, keep it well watered and fed, and top-dress each spring. Divide it every few years before it becomes pot-bound.
The permanent fix: choose clumping bamboo
If you would rather not think about barriers and spades, plant a clumping bamboo such as Fargesia instead. It expands by only a few centimetres a year to form a tidy clump and never runs. Every bamboo in our bamboo plants collection is a well behaved clumping variety, and they give the same lush, evergreen screening and privacy with none of the maintenance. To understand how quickly they establish, see how fast bamboo grows.