Interactive map lets you find where dangerous giant hogweed grows

A UK garden review site has launched a new map showing the locations of the poisonous plant Heracleum mantegazzianum, better known as Giant Hogweed.

The map is crowdsourced and then the platform searches for members of the public to submit possible sightings of the plant, with pests already identified in west London, Edinburgh and Manchester.

The map, created and maintained by, follows the spread of Giant Hogweed in the UK following the closure of the PlantTracker app.

The PlantTracker app was created as a joint effort of the Environment Agency, Natural Resources Wales, Scottish Natural Heritage and the Scottish Environment Protection Agency, but is no longer working due to a lack of funding.

Follow this link to get the current map, status of Giant Hogweed in the UK and to submit a sighting:

Heracleum mantegazzianum, more commonly known as Giant Hogweed, is often referred to as ‘Britain’s most dangerous plant’ because of the burning and scarring it can cause. The juice of the plant contains furocoumarins, organic chemical compounds that are toxic to humans. The compounds seep into the skin cells, which prevents the skin from fully protecting itself from sunlight, leading to skin damage.

Short-term symptoms of coming into contact with giant hogweed include blistering, irritation, and inflammation, and long-term symptoms include malformation, purple spots, and severe scarring. These symptoms can persist for months or even years after first contact.

As it stands, the map currently shows giant hogweed infestations in West London, Edinburgh and Manchester with pieces of the plant seemingly growing in East Kent and Chester.

Giant hogweed is often found along river banks while the seeds are transported by rivers. When fully grown, the plant can reach a height of 5 meters with a total spread of 1 – 2 meters. To spot giant hogweed shared information to identify the dangerous plant:

Stems – green with purple spots and white hair. They have a thick circle of hairs at the base of each stem.

  • Leaves – very large and can span up to 1.5 m wide and 3 m long. The leaves are divided into smaller leaves and resemble a rhubarb leaf, with a hairy underside.
  • Flowers – appear in June and July these are small clusters of white flowers that point upwards.
  • Seeds – about 1 cm long and dry, flattened and oval.

Kate Fromings of, said: “As gardeners and outdoor enthusiasts, we believe it is important to take responsibility when we enjoy these spaces. Whether it is by picking up litter or reporting Giant Hogweed sightings, we believe this is the right thing to do and encourage others to do the same.

“It’s such a shame that the previous tracking app could no longer find the money to continue. It is a good cause and so we hope the wider community can contribute. These plants are annoying and can harm humans and animals, so the sooner we spot them, the sooner we can warn others and help them enjoy the outdoors safely. “