The River Annan
The River Annan Trust & District Salmon Fishery Board
Giant Hogweed (Heracleum mantegazzianum)
Invasive Species
Contact Us
Fisheries Office
Annandale Estates, St Ann's
Lockerbie
Tel: 01576 470600
Mobile: 07710331079
E-mail:
Easy to identify when fully grown by its height, size of leaves and size of flowers. Its spreads solely by seeds and is capable of producing up to 50,000 of them. Seeds can remain viable for up to 15 years.
Key ID Features
White flowers up to 500mm across - in a large umbrella like flower (June - July)
Leaves are dark gren with a jagged appearance and spiky at the ends
Bristles on underside
Lower leaves can be up to 1.5 metres long & grow in a rosette
Can grow up to 5 metres tall
Green stems with dark-red or purple blotches
Stems often with sharp brissles
Image: RPS group Plc
Image: RPS group Plc
Image: RPS group Plc
Best Methods of Control
- Spraying with a commercial glyphosate-based chemical is effective on giant hogweed. The plant needs to be sprayed when the leaves are fully out but before flowering. Any re-growth can be sprayed later in the season. The plant should be controlled in 2-3 years, but will need future checking for any newly germinating seeds
- Cutting stems before the plant flowers and sets seed is effective on giant hogweed with eradication being achieved in 2-3 years. This should only be undertaken by a qualified person
- Giant hogweed can be disposed of by burning
- Never throw away or fly tip plant material or soil – under the Wildlife and Countryside Act 1981, it is an offence “to plant or otherwise encourage in the wild” the growth of giant hogweed
- Giant hogweed should not be touched without protective clothing as contact with the sap can produce a painful skin condition.
- Scottish Environment Protection Agency (SEPA) must be contacted before using chemicals in or near water.
- Be careful not to transport seeds to new sites
- Removal of plant material off site must be undertaken by a licenced carrier
- Report giant hogweed to invasives@annanfisheryboard.co.uk
Do's & Don'ts
