How Do I Stop Blackberries Spreading Everywhere?

Blackberries are vigorous plants with two spreading mechanisms: long arching canes that root at the tip when they touch soil, and underground suckers that send up new shoots several feet from the parent plant. Without management, a single blackberry plant can colonise a substantial area of garden within three to five years. The good news is that both mechanisms are easy to interrupt once you understand them.

Stopping tip-rooting

New canes (primocanes) grow from the base of the plant through the summer. If the arching tip of a cane reaches the ground and makes contact with soil, it roots within a few weeks, producing a new plant at that point. To prevent this, tip-prune every new cane in July and August — cut back the growing tip by 15–20 cm. The cane will grow no further and will not root. This is a routine summer task for contained blackberry growing.

Managing suckers

Suckers emerge from the root system at a distance from the main plant. Pull them up as soon as they appear — do not cut them at ground level as this stimulates further sucker growth from the same root. Pull or dig out with the root connection intact. Persistent suckering in a wide area can be reduced by severing the connecting root with a spade at the point where it leaves the main root zone.

Training on a fixed support

Training all canes onto a fixed wire fence or trellis and tying them as they grow removes the spreading habit almost entirely. Tied canes cannot reach the ground. This method also dramatically improves fruit production by keeping all fruiting wood in sunlight and improving air circulation. A post-and-wire system with two or three horizontal wires at 60, 90 and 120 cm is sufficient for most garden blackberry varieties.

Choosing a less vigorous variety

If spreading is a persistent problem, consider replacing the plant with a thornless, compact variety bred for garden growing (e.g. Loch Ness, Loch Tay). These varieties are far less vigorous than wild-type blackberries and produce little or no suckering. They still produce excellent crops but are much easier to contain.