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Revealed: Japanese knotweed reports in Peterborough

Now that summer is officially here, sightings of one of the UK's most invasive species of plant are expected to soar - with several occurrences reported in Peterborough.
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Japanese knotweed is often misidentified as bindweed or ivy

Throughout spring, Japanese knotweed emerges from the ground as purple or red asparagus-like shoots, before growing into lush green shrubs with heart or shovel-shaped leaves. It can grow up to 10cm a day between May and July and by mid-summer reach heights of around three metres. 

Japanese knotweed expert Environet has created a live online tracker to help people locate and record the pest plant.

The tracker identifies 21 knotweed reports within 4km of central Peterborough, using the postcode PE1 1HF for Bridge Street.

peterborough-knotweedThe heatmap shows the number of reported occurrences of Japanese knotweed. By Environet

New research suggests that only 18% of adults in the east of England can correctly identify the plant from other species commonly found in British gardens.

According to Environet's research, approximately 5% of homes across the country are currently affected by the invasive plant, knocking around £20bn off UK house prices.

In the east of England, 3% of properties currently lived in are affected, and a further 2% impacted because of the plant growing on a neighbouring property.

Although it's not illegal to have Japanese knotweed on your property, you should aim to control it. Homeowners looking to sell are expected to declare it and provide a management plan.

Environet say that the general public can help in the fight against knotweed by reporting suspicious plants using its heatmap’s ‘Add Sighting’ feature and attaching a photo to be verified by experts. 

Users who want to check on an area can enter a postcode to discover the number of reported knotweed sightings nearby, and hotspots are highlighted in yellow or red, like a traffic-light system.

What is Japanese knotweed?

Japanese knotweed was brought into the UK in the 1840s as part of a shipment of 40 boxes of Chinese and Japanese plant species delivered to Kew Gardens. It was intended to be an ornamental garden plant, but has since become an invasive non-native species which needs to be controlled.

According to the Royal Horticultural Society, Japanese knotweed rarely sets seed in this country but can sprout from very small sections of creeping underground stems, known as rhizomes. It is an offence to cause it to grow in the wild.

How should Japanese knotweed be dealt with?

Despite its fearsome reputation, the plant can be dealt with - but it's best to seek professional help.

While it may be tempting to dig out the plant at root level, disposing of it can be challenging as it's classed as 'controlled waste' under the Environmental Protection Act 1990 and therefore requires disposal at licensed landfill sites. It should never be included in normal household waste or put out as part of green waste collection schemes.