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.
Giant hogweed is an invasive species introduced to Britain as an ornamental plant in the 19th century. The sap of the giant plant can cause severe burns if it comes into contact with human skin. Pictured on the banks of the River Irwell, Bolton, June 24, 2025
‘Britain’s most dangerous plant’ has hit its scorching peak, experts have warned – and it could leave children, parents, and even pets with gruesome burns
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.
As the map shows, giant hogweed has a heavy presence across the whole of the UK, but especially in London and the north west
Giant hogweed (Heracleum mantegazzianum) can grow to 10 feet in height or even more – but it can cause nasty rashes upon contact
Once a person touches the sap and is exposed to sunlight, they can suffer phytophotodermatitis – an inflammatory reaction characterised by huge blisters and scars
Dog walkers are also being urged to keep their pets away from giant hogweed, as it is harmful to animals as well as humans
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 sap of the giant hogweed stops our skin protecting itself against the sun, meaning victims face painful, pus-filled blisters if exposed to daylight
Last summer, Ross McPherson was left with a blister as big as an orange and struggling to dress himself after brushing past a giant hogweed in Dunbar, East Lothian
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.
This article was originally published by a www.dailymail.co.uk . Read the Original article here. .