Without you even realising, your garden could contain a thug of the plant world, a thug which spreads like wildfire and is so invasive it could wreck your chances of selling your home.
The name of this terrible thug? Japanese knotweed.
This clump-forming perennial produces stems similar to bamboo that can grow to a height of 3m or more at a phenomenal rate – 1m in just a month – and that’s not the only problem.
As well as growing fast, it’s extremely invasive, reproduces very easily and is difficult and expensive to get rid of for good.
The plants are capable of breaking through Tarmac and weak points in concrete and of causing substantial structural damage to buildings.
They overwhelm other garden plants and can increase the risk of soil erosion and flooding.
Japanese knotweed can even ‘play dead’ – rhizomes can stay dormant underground for as long as 20 years before producing plants.
Eradicating Japanese knotweed can take several seasons and while it’s possible to do it yourself, a specialist contractor will be able to do it quicker and should be able to ensure it doesn’t come back, which is the tricky bit. Check that your contractor is qualified to deal with Japanese knotweed – if taken off site, it must be disposed of by a licensed waste control operator (your local council may be able to recommend some) at a licensed disposal site, because it and any affected soil is considered ‘controlled waste’. Soil containing rhizomes must be buried at least 5m deep and covered with a root-barrier membrane, making it a major undertaking.