My tenant is a keen gardener and has identified Japanese knotweed in the garden of my property. Is this a problem?
Japanese Knotweed is a tricky plant, and the enemy of gardens (and buildings!) everywhere. Introduced into the UK from Japan way back in the 1840’s, the plant was originally intended as an ornamental plant, but it is now known as the UK’s most intrusive plant species – causing damage to waterways, railways and most significantly, property.
It can be tricky to spot, so firstly, make sure your tenant has identified to correct plant.
In the early spring, reddy purple shoots will emerge from the ground, rapidly forming sturdy ‘canes’. Spade-shaped green leaves with quickly unfurl from these canes, and by early summer you could be looking at a plant up to around 3m high. By mid-late summer, white flowers will be blooming.
Autumn / Winter
The plants seem to die in autumn, with the leaves dropping, although the canes will remain standing.
Japanese Knotweed is insatiable in it’s quest for growth, and has been known to crack concrete, drains, paving and brick walls in order to expand – even growing in cavity walls and eventually forcing them apart - so if you think you have identified it, you need to move quickly, the sooner it is dealt with, the better!
You have two options for destroying the plant - herbicide treatment, or removal. Herbicide treatment is usually the cheaper option but will take at least one complete growth cycle, so you could be looking at a year’s worth of treatment, and the ongoing patience of your tenant. Removal is a swifter option, but isn’t always possible depending on where the plant is growing. Seek the advice of a Japanese Knotweed specialist to advise on your situation, but whatever you do – do it quickly!