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Do YOU live near a giant hogweed hotspot? Interactive map reveals the UK areas where Britain's 'most dangerous plant' has been reported
When it comes to invasive plants in the UK, giant hogweed is perhaps the most feared.
Often described as the 'most dangerous plant in Britain', giant hogweed looks harmless enough with its pretty white flowers.
But the sap of the non-native invasive species can cause nasty burns and blisters bigger than golf balls.
Now, a new interactive map helps you avoid the dreaded vegetation, which can even blind people if the sap gets into the eyes.
The map reveals the parts of the UK where sightings of giant hogweed – which tends to flower in June and July – has been reported.
It means when you're planning your summer walk, you can steer clear of any giant hogweed hotspots.
So, is there any giant hogweed in your area?
Scroll the interactive map to find out.
The new map comes from WhatShed, a British website that reviews and compares prices in the UK garden market.
In a blog post, it warns that even just lightly touching the plant's sap can pose a 'considerable threat to human health'.
'The spread of this invasive species across the UK has become increasingly rapid, it must be stopped,' it says.
As the map shows, giant hogweed has a heavy presence across the whole of the UK, but especially in London and the north west such as Manchester and Leeds.
Some of the sparser areas with fewer reported sightings are north and central Wales, Devon, Cornwall and the west of Scotland.
However, this doesn't mean giant hogweed doesn't have a presence in these regions.
That's because there's likely been sightings of giant hogweed across the country that have gone unreported or unnoticed.
WhatShed's blog post also allows you to report a sighting of giant hogweed in your area, which can then be added to the map to make it a more reliable tool.
How to spot giant hogweed
While the plant looks very similar to common hogweed, it is much larger and will often reach heights of over 16 feet.
Sharing tips on how to distinguish between the two plants, Mr Knight said the plant has 'long stems topped with umbrella-like clusters of tightly packed white flowers'.
'The large stems are covered in tiny white hairs and there are purple spots randomly dispersed all over the stem too with each branch tending to have a patch of purple colouration where it meets the stem,' he said.
Giant hogweed (Heracleum mantegazzianum) is a member of the carrot family that can grow to a striking 10 feet in height.
It has thick and bristly stems that are often blotched with purple, while the flowers at the very top are white and come in clusters that spread from a common point.
The sap of giant hogweed contains furocoumarin, which makes skin extremely sensitive to sunlight (phytophotodermatitis).
If the sap gets onto your skin and it's then exposed to the sun, your skin can get huge blisters, which can then recur over months and even years.
And because it causes no immediate pain, those affected may continue to enjoy the good weather, unaware of any problem until the first burns appear.
'The sap can pass through clothing when people are cutting it down,' writer and plant expert Geoff Dann told MailOnline.
Giant hogweed comes from southwest Asia and was first reported in the wild in the UK in 1828 in Cambridgeshire after being imported as an ornamental plant.
Today, it is particularly abundant along river banks and ravines, so gardens nearby to this type of terrain are most likely to have it growing.
It can also be found on motorway embankments and lining A-roads, where cyclists often brush past it, which can be enough to transfer the sap.
The plant reaches its greatest extent in June and July, according to Callum Sinclair, project manager with the Scottish Invasive Species Initiative.
'By the time we get to this time of year, they're pretty impressively-big plants and impressively-dangerous plants as well obviously,' he said.
'They're probably close to sort of maximum height now and mid-summer, July and August.'
There are other species in the hogweed family, including common hogweed (Heracleum sphondylium), which is smaller.
Although it also causes rashes and other skin complaints, reactions tend to not be as severe compared with the larger species.
'The fully-grown giant hogweed plant is unmistakably enormous, the foliage is shiny and much less hairy than hogweed and the lobes much more sharply toothed,' said Dann.
Seven of the world's deadliest plants
1. Water Hemlock (Cicuta maculata). A large wildflower in the carrot family, water hemlock is sometimes confused with edible parsnips or celery.
However, water hemlock is infused with deadly cicutoxin, especially in its roots, and will rapidly generate potentially fatal symptoms in anyone unlucky enough to eat it.
Painful convulsions, abdominal cramps, nausea, and death are common, and those who survive are often afflicted with amnesia or lasting tremors.
2. Deadly Nightshade (Atropa belladonna). A native of wooded or waste areas in central and southern Eurasia, deadly nightshade has dull green leaves and shiny black berries about the size of cherries.
Nightshade contains atropine and scopolamine in its stems, leaves, berries, and roots, and causes paralysis in the involuntary muscles of the body, including the heart. Even physical contact with leaves may cause skin irritation.
The sweetness of the berries that often lures children and unwitting adults to consume this lethal plant.
3. White Snakeroot (Ageratina altissima). A North American herb with flat-topped clusters of small white flowers and contains a toxic alcohol known as trematol.
Symptoms of 'milk poisoning' include loss of appetite, nausea, weakness, abdominal discomfort, reddened tongue, abnormal acidity of the blood, and death.
White snakeroot was responsible for the death of Abraham Lincoln's mother, Nancy Hanks. She was poisoned by simply drinking the milk of a cow who had grazed on the plant.
4. Castor Bean (Ricinus communis). Widely grown as an ornamental, the castor bean is an attractive plant native to Africa.
While the processed seeds are the source of castor oil, they naturally contain the poison ricin and are deadly in small amounts.
It only takes one or two seeds to kill a child and up to eight to kill an adult. Ricin works by inhibiting the synthesis of proteins within cells and can cause severe vomiting, diarrhea, seizures, and even death.
5. Rosary Pea (Abrus precatorius). Also called jequirity beans, these piously-named seeds contain abrin, an extremely deadly ribosome-inhibiting protein.
Rosary peas are native to tropical areas and are often used in jewelry and prayer rosaries.
While the seeds are not poisonous if intact, seeds that are scratched, broken, or chewed can be lethal.
6. Oleander (Nerium oleander). A beautiful plant known for its striking flowers.
Though commonly grown as a hedge and ornamental, all parts of the oleander plant are deadly and contain lethal cardiac glycosides known as oleandrin and neriine.
If eaten, oleander can cause vomiting, diarrhea, erratic pulse, seizures, coma, and death, and contact with the leaves and sap is known to be a skin irritant to some people.
7. Tobacco (Nicotiana tabacum). Tobacco is the most widely grown commercial non-food plant in the world.
All parts of the plant, especially its leaves, contain the toxic alkaloids nicotine and anabasine, and can be fatal if eaten.
Despite its designation as a cardiac poison, nicotine from tobacco is widely consumed around the world and is both psychoactive and addictive.
Tobacco use causes more than 5 million deaths per year, making it perhaps the most deadly plant in the world.
