Japanese Knotweed: what is it, what does it look like- and hotspot areas in Birmingham

Japanese Knotweed is invasive and can impact gardens and homes- here’s what to look out for

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Following reports of a homebuyer successfully suing the former owner of the house after discovering large quantities of Japanese hogweed on the property, it could be worth a check to see where the invasive weed has been reported in Birmingham. Making a seller aware of the presence of Japanese Knotweed has been a legal requirement since 2013 and, in this most recent case, saw the vendor of the property ordered by the court to pay out a settlement of £200,000.

Japanese Knotweed is one of the biggest headaches for gardeners across the UK as it can grow at rapid speeds and take over gardens and buildings. According to invasive plant specialists, Environet, not only can the plant present problems to surrounding flora but it can also block drains, destroy asphalt, collapse brick walls, damage cavity walls and lift patios, among other costly issues.

Being on the lookout for the weed is one of the first preventative steps you can take. Keeping it contained and treating it quickly are perhaps easier said than done, but there is plenty of help out there.

The Royal Horticulture Society defines Japanese Knotweed, or Reynoutria japonica to give it its latin name, as “a weed that spreads rapidly. In winter the plant dies back to ground level but by early summer the bamboo-like stems emerge from rhizomes deep underground to shoot to over 2.1m (7ft), suppressing all other plant growth. Eradication requires determination as it is very hard to remove by hand or eradicate with chemicals.”

Japanese Knotweed can be found from spring through to autumn, and should be treated in the summer months. One of the main issues with the weed is its creeping roots.

What does Japanese Knotweed look like?

According to the RHS, Japanese Knotweed has reddish/purple shoots which emerge in spring. These grow rapidly, producing in summer, dense stands of tall bamboo-like canes which grow to 2.1m (7ft) tall. These canes have characteristic purple flecks, and produce branches from nodes along its length.

Leaves are heart or shovel-shaped and up to 14cm in length and borne alternately along the stems. The stems die back to ground level in winter, but the dry canes remain for several months or longer.

Japanese Knotweed hotspots in the West Midlands

In the West Midlands, there are many reports of Knotweed.  According to Environet interactive knotweed map,the Kings Heath area of Birmingham is the location of a high number of cases along with North East Birmingham, just to the south of Aston, also receiving a number of reports.

The hotspot checker is updated using data collected from around the country. To check out where you live, enter your postcode on  their website.