Bamboo Spreading Under The Fence

What's happening?

The RHS says running bamboos spread by rhizomes, underground stems that can grow shoots and roots from any node along their length. In favourable conditions the rhizomes can spread over 1 metre each year, often unnoticed until they send up shoots. Running types spread quickly, are difficult to eradicate once established and are often viewed as weeds. Bamboo can regenerate from any section of rhizome with a node, and rhizomes can easily spread a few metres from the plant. Shoots coming up in your garden are from a clump on the other side of the boundary or from your own plant. It is a different plant from Japanese knotweed and from horsetail, with different control methods.

What usually causes it?

• A running bamboo planted without a root barrier, next to the boundary
• Rhizomes travelling under a fence, path or wall to the other side
• Pieces of rhizome left in the soil, which regenerate from any node
• A bamboo that has been left unmanaged for years
• A clump-forming bamboo mistaken for a running one, or the other way round

Is it dangerous?

No. It is a nuisance, and the RHS says the shoots compete with other plants for moisture and nutrients. A dispute over a neighbour's bamboo is a civil matter between neighbours, so try to settle it with them first.

Can I fix it myself?

Cut or dig out the shoots in your garden and trace the rhizomes back. The RHS gives three options. At planting, dig a trench at least 60cm deep around the bamboo and insert a physical barrier that extends at least 7.5cm above soil level. For an established clump, dig a trench about 30cm deep and a spade wide, 30-50cm from the plant, sever the rhizomes you find, remove the sections beyond the trench and backfill: the RHS says this suits clump-forming and slow-growing running bamboos, and doing it at least once a year keeps many bamboos under control. Or dig out the whole plant and monitor for regrowth. It does not support weedkillers and says that even repeated systemic treatment can take several years to kill a bamboo. Do not compost rhizome pieces. You can only trim roots and branches back to your own boundary. Talk to the neighbour about a barrier.

When should you call a gardener?

Call a gardener to dig out spreading rhizomes, trench and fit a root barrier on your side, or to remove a whole plant. Agree with your neighbour first if work is needed on their side.

What will the gardener actually do?

• Trace the rhizomes and dig out shoots and runners on your side
• Trench along the boundary to cut the rhizomes, and fit a root barrier set 7.5cm above soil level where a new planting is made
• Dig out an unwanted plant completely and monitor for regrowth
• Remove the waste rather than composting it
• Advise on clump-forming alternatives or growing bamboo in pots or raised planters

Who fixes this

• Weeding and border care

Questions people ask

Sources & References

1. RHS: bamboo control in gardens
2. GOV.UK: resolving neighbour disputes, high hedges, trees and boundaries