Disputes relating to Japanese knotweed due to "encroachment"
the spread of knotweed rhizomes (roots) across property boundaries

What happens if Japanese knotweed encroaches to or from adjoining land?

The legal remedy for knotweed spreading into your land from adjoining land can be found in civil nuisance. To bring a successful claim, the claimant needs to demonstrate that the knotweed originated from the adjoining land, and that the knotweed is causing the claimant owner "nuisance".

It's not always easy to demonstrate the knotweed origin, making a case difficult and expensive to prove.

If the adjoining landowner, the defendant, is seen to be taking reasonable steps to mitigate the nuisance that may in itself may be a suitable defence, making any claim likely to fail.

You should think very carefully before embarking on legal redress, as it is expensive, risky and not great for future neighbour relations.

What practical measures can I take to stop Japanese knotweed encroaching onto my land from my neighbours?

Japanese knotweed is not fussy about where it grows, but it has an uncanny desire to grow along and cross property boundaries. Without any respect for the poor human that owns the land, it spreads its invasive rhizomes and continues to encroach and wreak havoc until action is taken against it.

The damage Japanese knotweed can cause should not be under-estimated, so if you notice Japanese Knotweed encroaching onto your land, you should take action.

Notify the adjoining land-owner of the problem, preferably in writing. A coordinated approach that tackles the Japanese knotweed on both pieces of land is much more likely to be successful than piecemeal attempts. Talk to us for a Treatment Plan and try and agree with the adjoining land-owner the allocation of costs.

If you can’t agree a way forward with the adjoining owner, (some are more receptive and motivated than others), we can control the encroachment using herbicides. 

What about using vertical root barriers?  

Vertical root barriers can be installed along the infested boundary, which if done correctly should prevent further encroachment. This involves excavating a trench at least 2m deep, installing a proprietary root barrier membrane, then backfilling.

There are practical difficulties in doing this, especially where services or tree roots also cross the boundary. Costs are very high, and the money is usually better spent controlling, or eradicating the knotweed in the adjoining land, rather than trying to contain it with root barriers.

This method is therefore seldom used, unless carried out with other major excavation works.

Still want to pursue Legal Redress?

If you do need assistance one of our experts can provide Japanese knotweed expert witness services in accordance Civil Procedure Rules (CPR 35). We can also put you in touch with legal experts, highly experienced in Japanese knotweed disputes.

Contact us.