New data has revealed the South East London hotspots where Japanese Knotweed, the UK’s most invasive plant, is running wild.

The invasive plant species is responsible for damaging homes, pavements and drains and can spread up to seven metres horizontally.

As Japanese Knotweed growing season is getting underway, one invasive plant specialist has revealed the knotweed hotspots for spring.

Environet UK used data on sightings to create this online map.

There are currently almost 57,000 known occurrences of the UK’s most invasive plant.

News Shopper: Japanese Knotweed hotspots in South East LondonJapanese Knotweed hotspots in South East London

Across South East London there are a lot of areas that have reported Japanese Knotweed

Bromley has 71 occurrences within 4km whereas Lewisham has over 107 occurrences also at 4km. 

But taking the crown for the most in the area is Greenwich with more than 157 occurrences of the weed also within 4km.

How to spot Japanese Knotweed

Knotweed hibernates over winter but in March or April, it begins to grow, with red or purple spear-like shoots emerging from the ground which quickly grows into lush green shrubs with pink-flecked stems and bamboo-like canes.

For homeowners, the plant can pose serious problems if left unchecked, with the potential to grow up through cracks in concrete, tarmac driveways, pathways, drains and cavity walls.

The roots can grow as deep as three metres and spread up to seven metres horizontally. While serious property damage is rare thanks to regulation which requires knotweed to be dealt with, it commonly impacts use of the garden, causes legal disputes between neighbours and can impact a property’s value by around 5%.

What to do if you have Japanese Knotweed


The first step to tackling the plant is to commission a professional Japanese Knotweed survey and find out the extent of the infestation. They will be able to tell you where it originated, and the best way to tackle it.

Professional treatment should then be organised, which usually involves the use of herbicide for the excavation of the infestation.

If you’re buying a property and you want to be sure it’s clear of knotweed, particularly if it’s located in or near a hotspot, arrange a detection survey.