The best thing you can do if you’ve got if you’ve got Japanese Knotweed, is to control it as it’s highly unlikely that you’ll be able to make a successful claim for any damage caused by it.
When it comes to keeping the plant at bay, it’s always best to get a pro in – doing it yourself might be cost effective in the short term but if you don’t know what you’re doing, you could end up inadvertently spreading it. Japanese Knotweed seeds aren’t fertile in the UK so the plant spreads through its roots – and even a tiny bit of it can sprout new shoots – so it’s best to be cautious.
If you have Japanese Knotweed and don’t keep it under control and it spreads into neighbouring gardens, then you could be held responsible for any damage it causes. If your insurance provider isn’t willing to cover the cost of the damage caused and you don’t agree the damage is your fault and refuse to pay, then you could face legal proceedings as your neighbours seek compensation to cover the cost of damage caused by your wild weed.
If you do end up needing to take things further and the law gets involved, your home insurance may cover you for legal costs if your policy includes legal protection in the event of a legal case being taken against you. You’d need to make sure you read the T&Cs of your legal expenses contract carefully though and discuss it with your provider before you start – because costs can rack up.