Giant hogweed

What is giant hogweed?

Giant hogweed is an invasive plant that has become common in many areas across the UK. Chemicals in the sap react to sunlight and if it comes into contact with skin can cause effects ranging from a mild rash, blistering and scarring which may require hospital treatment.

In Torfaen, giant hogweed is extremely rare, with only about three instances of the plant discovered in the borough in the last 30 years.

Identifying giant hogweed

Giant Hogweed

Giant hogweed is notable for its size and can reach more than 10 foot in height. The flowers are white and grow in flat-topped clusters. The flower heads can be as large as two foot across.

The giant hogweed factsheet has some additional information which may be useful in identifying giant hogweed.

Most reports of giant hogweed in Torfaen are actually of common hogweed. Common hogweed is a member of the same family of plants, however, it is significantly smaller than the giant variety. Common hogweed is found right across Torfaen, on almost every road verge and in many open spaces. It is a desirable plant to have in the borough as it plays a key part in the local ecosystem, attracting many pollinating species.

Plants such as cowbane and cow parsley (also members of the same family) are also often mistaken for giant hogweed. While they may look similar they are significantly smaller in size.

Giant Hogweed in a private garden

If you are concerned that you have giant hogweed in your garden you can contact Natural Resources Wales for advice.

Reporting giant hogweed in a public area

All reports of giant hogweed in Torfaen are taken seriously. You can help us to identify any instances of giant hogweed by providing the following information:

  • A detailed description of the plant, including the estimated height and the size of the flowers
  • The exact location of the plant (A street or road name, a house number, or street light number in close proximity to the plant would be very useful incase we need to investigate in person)
  • A photograph of the plant to allow us to make an identification

In most cases we will be able to determine if the plant in question is giant hogweed based on this information. If not, we will investigate in person.

Reports should be made via Call Torfaen on 01495 762200, or via

Last Modified: 05/12/2018
For more information contact:

Call Torfaen

Tel: 01495 762200


Back to top