00642 Verges Booklet - Devon County Council

(viii) Giant Hogweed (Heracleum mantegazzianum)
Description
Starts growing in March-April, reaching 3 to 5 metres in
height. The leaves are dark green, in a rosette, lobes
deeply cut and spikey at the ends.The stem is dark redpurple
spots or blotches up to 100mm across. The
flowers are white forming one large umbrella-like
flower head that appears in June-July.
Legislation
The Wildlife and Countryside Act 1981 makes it an offence to plant or
cause Giant Hogweed to grow in the wild.
Further Information and Control
Giant Hogweed, a native of the Caucasus mountains between Russia
and Turkey, was introduced to Britain as an ornamental plant in the late
19th Century. It is now widespread throughout the British Isles
especially along river banks.
The control of these plants by non-chemical methods should always be
considered as the first option. However, this form of management is
often labour intensive and time-consuming. Plants may be dugout, but
care should be taken to remove much of the root stalk. Cattle, sheep,
goats and pigs are also cited as possible methods of control as they eat
Giant Hogweed without apparent harm, trampling also damages the
plant.
Chemical control should only be considered only after non-chemical
control has been evaluated and has proved impracticable.The herbicide
glyphosate is currently the most effective chemical control for Giant
Hogweed.
WARNING
The hollow stems are attractive to children who use them as “pea shooters”
and “telescopes”. However the stems and edges and undersides of the leaves
bear small hairs which are coated with poisonous sap and causes blistering
and severe irritation. It should not be touched without wearing protective
clothing. Giant Hogweed is a potential danger to public health. Seek medical
advice if blistering occurs.