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Beware the Japanese Knotweed

  • 5 years ago

Spring is the time that you’ll see the scourge of Japanese knotweed start to do its thing. Its thing is, unfortunately, overgrowing native plant species and reducing the value of your property, so if you see it, you’ll need to take action immediately.

By summer, the plant is in full flow, before it dies back in autumn and winter. Even if you’ve had a really good go at it, all it’s done is retreat, ready to come back with a vengeance next spring. That’s all well and good, you might think; that’s what most plants do. Japanese knotweed, however presents serious problems for your property’s structural integrity.

Deep-rooted issues

We’re often so surprised at the speed this plant sends out shoots in spring and summer – up to 20cm in 24 hours – that we ignore what’s going on underground. You can cut and rake the visible plants to save your garden, but unless you kill the roots, it’ll keep coming back. You’ll find it almost impossible to locate and dig out every single root by yourself, though, so each spring you’ll face the same foe. What’s worse is that each spring gives the plant more chances to damage your walls and foundations.

The roots of the Japanese knotweed can burrow into cracks in walls and under the foundations and as the plant grows, so do the cracks. Once knotweed has taken hold of a building, it’s vulnerable to damage and if you’re trying to get a mortgage for a house with it, you’ll find it nigh-on impossible.

Call in a professional

Most lenders will simply refuse a mortgage application if a surveyor spots Japanese knotweed and the only way to remedy the situation is to call in a professional removal service. You’ll be doing yourself a huge favour even if you’re not planning to buy or sell the property because while you can keep it in your own garden (which is somewhat foolhardy), you’d be breaking the law if you allowed it to spread onto a neighbouring property.

There are also penalties for digging it up and failing to dispose of it properly. If you have a pile of knotweed and you simply bury it elsewhere, you run the risk of it thriving out of sight and causing havoc eventually.

Combating Japanese knotweed

You may have been fighting the good fight yourself for a number of years, wondering why the knotweed Just. Won’t. Die. You may be at the point of a slash-and-burn solution, but even this won’t do the job unless you scorch the earth to a depth of a few feet. Which is probably even more illegal than keeping the knotweed…

A tough job needs tough tools

If you call in the professionals, they can use very powerful herbicides that you won’t find at your local garden centre. If you’re not planning to sell or buy the property, these solutions can take a few growing seasons to totally eradicate the problem, but they will work. You should choose a team that can offer you an insurance-backed guarantee against re-infestation of at least five years.

If you need the weed to be gone quickly, then a dig-out will be necessary. This process will get rid of all the knotweed roots but cause the minimum of disruption to the rest of the soil and garden. Your team can also dispose of the dead plants properly so they’ll never come back to haunt you…

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