Don’t be fooled, the cold snap has delayed the start of the growing season

What to expect after the coldest February in five years

Normally we would see Japanese knotweed shoots springing up in warmer parts of the country and in sheltered urban areas during the middle of March, but the recent cold snap has set the start of the growing season back by at least a fortnight, possibly as much as a month.

The ‘Beast from the East’ brought the coldest February week in five years last month and the Met Office is forecasting lower-than normal temperatures for the rest of March. Japanese knotweed won’t awaken until the ground temperature reaches around 4°C, when it will emerge to begin its annual assault on property foundations, patios, driveways, cavity walls and drains.

We would advise you to remain vigilant once the warmer weather arrives. Look out for signs of red or purple asparagus-like shoots which emerge from the ground and quickly turn into green bamboo-like stems. They grow at a rapid rate, up to 10cm per day, to reach up to 3 meters in height by June. 

The plant has flat, heart-shaped green leaves and blooms in late summer, when its stems become covered in tiny creamy-white flowers. If you’ve seen a plant growing in your garden that fits this description but you’re unsure what it is, we offer a free identification service. Just email a couple of photos to expert@environetuk.com and we’ll let you know if it’s knotweed. Or watch our short video on identification here.

Japanese knotweed has spread so rapidly across the UK in the last decade that it’s really no longer a case of winning the battle. Those who discover knotweed on their land should take immediate action and put a professional treatment plan in place to protect their property and protect themselves against litigation from their neighbours. While it isn’t illegal to have Japanese knotweed growing on your land, you can be sued if you allow it to spread onto a neighbouring property. 

You must also declare the presence of knotweed on the TA6 conveyancing form when you sell your home, even if it has been successfully treated. 

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