Giant Hogweed

Heracleum mantegazzianum

Description

Tall perennial herb, with individuals growing up to 5 meters tall with a white umbel flower head emerging in late summer. Leaves are deeply lobbed with dark purple blotches on the hairy stems. Emergent leaves significantly different to those of a mature plant, being less lobed.

Distribution

Located throughout Great Britain.

Habitat

Usually located along waterways in both urban and rural areas. Naturally found in the Caucasus Region and Central Asia.

Impact

Giant hogweed is able to outcompete native species and create monocultures in areas of suitable habitat. Furthermore contact with this plants sap can result in severe burning and blistering of the skin after exposure to sunlight. The plant grows readily in publicly accessible open spaces which increases the issues of public exposure to this plant.

Control and Management

Control and management techniques vary depending on the site and situation. The following information needs to be evaluated for each site.
Manual Removal:
a. Seeding plants: Cut off seed head to stop seed spread. May-September.
Chemical:
a. Glyphosate. May to September.

Recommended Action

1. Map individuals and populations and share data with LISI.
2. Organize removal and education programmes where and if appropriate.
3. Follow treatment information where appropriate. Before work ensure you have all correct licence and certificates for the use of any herbicide or techniques being used.
4. Contact your local Borough or LISI for further information if required.
5. Monitor the site for seed regeneration and regrowth.

Health & Safety Guidance

As stated previously contact with this plants sap can result in severe burning and blistering of the skin after exposure to sunlight. Extreme care is needed when dealing with this species as burns can be severe. Full Personal Protective Equipment (PPE) is required when conducting treatment and should be considered carefully. If contact is made seek medical advise immediately to ensure best treatment is conducted.

Further Information

Further information is available on the Great Britain Non-Native Species Secretariat website www.nonnatives.org.uk

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