How Swindon and Wiltshire gardeners can stop Japanese knotweed

Japanese knotweed is the UK’s most invasive plant and poses a “significant” threat to properties.

It can cause structural damage, reduce property value, and make it harder to secure mortgages.

It is estimated that around 5% of homes in the UK are affected by the invasive plant, with more than 100,000 infestations reported to Environet.

What is Japanese knotweed?

How to identify Japanese knotweed

Key traits of Japanese knotweed to look out for, according to Environet, include:

Red shoots emerge in spring that look like asparagus

Leaves which are shield or shovel-shaped

Stems that resemble bamboo canes with purple speckles

Small, cream-coloured flowers developing towards the end of summer

Japanese knotweed has red shoots that emerge, which “look like asparagus”.(Image: Getty Images)

“Japanese knotweed is most easily identified during the spring and summer months.”

The experts continued: “In the autumn, the leaves will start to go yellow and drop as winter approaches.

“Knotweed can grow to about two or three metres if left unattended. The stems will change to a darker brown before the plant becomes dormant in winter.”

You can spot Japanese knotweed by the small, cream-coloured flowers that begin to grow towards the end of summer.

Japanese knotweed is an “amazingly resilient” plant and will grow “pretty much anywhere”.

The 3 simple steps gardeners can follow to prevent the spread of Japanese knotweed

The experts at Property Care Association (PCA) have issued a plea to gardeners in Swindon and Wiltshire, saying they have a “vital role” to play in helping prevent the spread of Japanese knotweed and other invasive, non-native plants (INNPs).

Poisonous plants found in the UK

Technical Manager of the PCA’s Invasive Weed Control Group, Daniel Docking, explained: “While experienced gardeners have a keen eye for plant species, there are many plant families, such as gunnera, rhododendron and bamboo, that have ornamental and invasive varieties which can be confusing.

“As part of a recent government consultation, we’ve called for better plant labelling to help householders understand what they are buying and for nurseries and suppliers to adopt Biosecurity Management Plans to help ensure businesses are working to reduce the risk of invasive plants spreading through horticultural pathways.”

So what can gardeners in Swindon and Wiltshire do to prevent the spread of Japanese knotweed and other invasive plants?

Simple ways to create a wildlife-friendly garden

These are the three things recommended by the PCA:

1. Know your nursery

The PCA said to start by chatting with the team at your local nursery or garden centre.

The experts added: “Ask about their labelling systems and any steps they take to highlight invasive species.

“Many popular ornamental plants such as montbretia and Virgina creeper are regulated by Schedule 9 of the Wildlife and Countryside Act 1981 which prohibits the release of any animal or plant species into the wild.”

2. Seek support

Invasive, non-native plants can often take root properties, and keen-eyed gardeners are often the “first line of defence” in ensuring the issue is dealt with quickly and effectively.

What to do if you spot Japanese knotweed (how to remove)

Confirm the identity of the plant by contacting Environet’s free ID service

Commission a professional Japanese knotweed survey to confirm the extent of the infestation, where it originated, and the best way to treat it

Organise professional treatment

The PCA said: “It’s essential to know which plants you can safely tackle yourself and when to call in an expert, such as a member of PCA’s Invasive Weed Control Group.

“Some species, such as Japanese Knotweed, should always be dealt with by a professional.”