JAPANESE KNOTWEED AND GIANT HOGWEED are some of the most invasive plants in the UK- and heatmaps has revealed where they are growing in and around East Lancashire.
These plants can be a nuisance to gardeners and one of them can even cause skin irritation, while the other has been known to cause irreparable damage to building infrastructure.
Here’s everything you need to know about Japanese Knotweed and Giant Hogweed- including where they are growing in and around East Lancashire.
What is Japanese Knotweed and Giant Hogweed?
Japanese Knotweed
Also known as Fallopia Japonica, this is a weed that spreads rapidly, with the stems growing up to 7ft tall and suppressing all other plant growth.
It often grows in dense thickets and can easily be identified by its bamboo-like stems and green leaves with ‘zig-zag’ stems.
It is notoriously hard to remove by hand or eradicate with chemicals.
“Its purple asparagus-like shoots will begin to appear around March/April and when the warmer weather arrives in May and June,” A spokesperson for Environet, invasive plant specialists, told The Lancashire Telegraph.
Although it looks harmless, Japanese knotweed can wreak havoc on our building’s infrastructure.
While it is not illegal for you to have it on your property, it is against UK law to cause or allow the plant to spread in the wild- you can be prosecuted for allowing it to do so.
You will also have to declare it when you sell your home- which can decrease your property value by 10%.
A spokesperson for Environet said: “Now number one on the Environment Agency’s list of the UK’s most invasive plant species, Japanese knotweed spreads through its powerful underground root system, pushing up through asphalt, cracks in concrete, drains and even the cavity walls of our homes in search of light and water.
“It can do vast damage to buildings and is notoriously hard to kill.”
Giant Hogweed
You’re most likely to see Giant Hogweed between June- August and it can be identified by its tall umbellifer and large, white, umbrella-like clusters of flowers.
It has a hollow, rigid which is purple-spotted, and it favours damp areas, such as riverbanks.
However, it gained a reputation as one of the UK’s most dangerous plants for its blister-causing sap.
After contact with the sap, the skin will start to blister and later form a brown scar; the skin will also be sensitive to sunlight for some time afterwards.
Medical professionals advise anyone who comes into contact with it to wash the areas affected with soap and water, and wear long-sleeved clothing.
Blisters and burns can occur if the skin is then exposed to direct sunlight, and if the plant touches patients' eyes they must report to A&E immediately as it can cause blindness.
A nature group in the North West, called Bolton NEWT, have warned people about the dangers of giant hogweed and even created a video to help identify the dangerous plant.
(Facebook/Bolton NEWT)
In the video they said: “The danger this plant poses are serious.
“It contains high quantities of toxic chemicals in its sap and skin… it can make your skin hypersensitive to UV light and this condition can last as long as six years.
“If the sap or hairs make contact with your eyes it can cause blindness.
“There are three important ways to identify the giant hogweed- it has gigantic leaves, there are purple blotches on the stem and it can also grow up to 15 ft in height.”
Invasive plant hot spots in East Lancashire
Japanese Knotweed
According to the data from an online tracker created by Environet there are more than 2700 reported occurrences of Japanese knotweed East Lancashire.
A spokesperson for Environet said the heatmap will be especially useful for homeowners or those looking to move house in the coming months.
They said: “It’s especially helpful for people buying homes so they can carry out checks or commission a Japanese knotweed survey if the property they want to buy is in a high-risk area.
“It’s really important to be armed with the facts, because if knotweed is present, a professional treatment plan will need to be put in place with an insurance-backed guarantee in order to satisfy mortgage lenders - and many buyers also renegotiate the price.”
With outbreaks of up to 364 within 4km radius, residents of Blackburn should keep an eye out for the knotweed.
In further parts of the Blackburn with Darwen unitary authority, there are more than 1014 reported occurrences withing a 4km radius.
In theb Hyndburn district there have been 363 reported occurrences.
In and around Burnley, 198 Japanese Knotweed sightings have been reported and in the Pendle district more than 300 knotweed hotspots have been reported within a 4km.
Giant Hogweed
This interactive map from whatshed.co.uk (garden building buyers guide) details where Giant Hogweed has been spotted across the UK- East Lancashire included.
There have been some reports of the plant growing in Pleasington.
Other sightings of the plant have been reported on the M65 between Tockholes and Ollerton Fold.
Another sighting was reported by the River Hyndburn near the town of Rishton.
The Clough Brook and River Calder near Altham Business Park are also hotspots for the invasive plant.
How do I get rid of these invasive plants?
Japanese knotweed is infamously hard to get rid of- but it’s not impossible.
According to the Royal Horticultural Society, you can try to use chemical controls on a small patch of area.
Similarly, you could try to dig out the deeply penetrating plant yourself.
However, seeking professional help is advised as Japanese knotweed is classed as 'controlled waste' under the Environmental Protection Act 1990, meaning it requires disposal at licensed landfill sites.
It cannot be included with normal waste or put in green waste collection schemes.
The Royal Horticultural Society also adds that it can take three or four seasons to fully eradicate the knotweed using regular weedkiller- but professionals will have access to more powerful chemicals that will reduce this time period.
In the case of giant hogweed, Blackburn council warn people not to touch the plant if you spot it.
Instead, contact them and report it.
If it’s on your land the Anti-Social Behaviour, Crime and Policing Act 2014 can be used to force landowners to take steps to destroy giant hogweed on their land that is judged to be causing serious problems to communities.
According to the government website, you can get rid of this plant by
- spraying plants with chemicals
- burying plants
- burning plants
- disposing of plants off site
Make sure to wear protective clothes if you are attempting this yourself.
In cases where your garden is overgrown with it or you’re concerned about your safety, leave it to the professionals.
Have you ever dealt with an invasive plant species? Send your stories to: sarah.mcgee@newsquest.co.uk
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