Japanese knotweedJapanese knotweed is an invasive plant species that grows rapidly and dies hard. While the law does not require you to take action if you find Japanese knotweed in your garden, you will get into trouble if you allow the plant to spread into the wild; for this reason, if you do have knotweed growing on your property, it’s a good idea to contact a qualified Japanese knotweed removal specialist who can get it under control.

But what if it’s your next-door neighbour who has a Japanese knotweed problem?

Well, ideally, your neighbour will act quickly and make sure the plant doesn’t spread onto your property. Unfortunately, not everyone is that proactive, so a certain amount of vigilance may be necessary on your part too.

Here are some tips to bear in mind if your neighbour has Japanese knotweed:

Start by talking to your neighbour. They may not be aware of the invasive weed that’s lurking in their garden—they may not even know what Japanese knotweed is, so be patient and politely suggest that they get in touch with a specialist contractor. It’s always better to resolve issues like this amicably if possible.

Remember, your neighbour is not breaking the law by having Japanese knotweed on their own property. UK law does not even require them to remove or treat the knotweed—only to prevent it from spreading elsewhere.

If your neighbour refuses to take action or acknowledge the issue, you should take the initiative and contact a qualified Japanese knotweed specialist yourself. They will be able to confirm the plant’s presence and can send your neighbour an official letter notifying them of their legal obligation to ensure that the knotweed does not encroach on your property.

Monitor the situation closely to see how it develops. Photographic evidence and regular reports from your knotweed expert will help you to demonstrate (if necessary) that your neighbour did not take sufficient action to prevent their Japanese knotweed from crossing the property boundary.

Japanese knotweed can have a significant impact on your property’s value and may even cause damage to the property itself, so it’s imperative to make sure you’re covered. A neighbour who has permitted Japanese knotweed to spread from their property to yours is legally liable, and you may be able to claim compensation—but only if you can prove what happened. This will be far easier if you have an expert witness to back you up (ideally a qualified professional who specialises in Japanese knotweed control and who has been monitoring the situation from the beginning).