An interactive map has revealed the hotspots in Hampshire where Japanese knotweed, one of the UK's most invasive plants, can be found.

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

Spring and summer are usually a prime time for the plant to spread so invasive plant specialist Environet UK has revealed the knotweed hotspots using data from its online map.

There are currently around 57,000 known occurrences as of the time of writing, which can be seen on the interactive map here.

Where are the Japanese Knotweed hotspots in Hampshire?

The most prominent spot for Japanese Knotweed in Hampshire is Southampton, which has 66 infestations within a 4km radius.

Daily Echo: The major hotspots were Southampton and PortsmouthThe major hotspots were Southampton and Portsmouth (Image: Environet)

Portsmouth is the next worst, with 44 infestations within the same radius, whilst there are 23 in Winchester and 18 near Havant. 

Smaller counts occur in places such as Petersfield (12), Bishop's Waltham (12), New Milton (10) and Romsey (4).

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 grow into lush green shrubs with pink-flecked stems and bamboo-like canes.

The roots can grow as deep as three metres and spread up to seven metres horizontally. 

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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.