Giant hogweed

How you can identify this toxic plant, the risks of contact and what you should do if you spot it.

What is giant hogweed?

Giant hogweed is a toxic plant that's part of the carrot family. It's sometimes found:

  • on waste ground
  • on river banks
  • beside roads and train tracks

What giant hogweed looks like

Giant hogweed can:

  • be up to 3.5 metres (11.5 feet) tall
  • span around 1m (3.5ft)

The plant's heads can be as large as 60 centimetres (2ft) across.

Giant hogweed has long, green stems which branch out into clusters of small white flowers. It's therefore sometimes confused with:

  • common hogweed
  • cow parsley
  • elderflower
  • bishop’s flower

However, you can tell giant hogweed apart from these other plants by its:

  • purple-hued stem
  • thin spines
  • leaf stalks covered in spots

Giant hogweed

You can find out more about the plant and its appearance in the Non-native Species Secretariat's guide to giant hogweed.

Why giant hogweed is dangerous

If your skin comes into contact with giant hogweed sap and is then exposed to sunlight, it can cause a condition called phytophotodermatitis. This is a skin reaction that can lead to:

  • blistering
  • changes to skin pigmentation
  • long-lasting scars


If you come into contact with giant hogweed, cover the affected skin and wash it with soap and water as soon as possible. If you feel unwell, contact your doctor or call NHS 24 on 111.

If you spot giant hogweed

Wherever you spot giant hogweed, make sure that you're very careful around the plant. Do not touch it.

Council land

If you know that the giant hogweed is on council land, you can report it by:

We always take giant hogweed sightings seriously and act quickly when we receive reports.

Private land

If possible, you should contact the landowner and let them know about the plant.

If you cannot do this, you can report it to the Scottish Invasive Species Initiative using their online form.