Sometimes also known as Giant Cow Parsley.
Native to mountainous regions of Turkey and Russia and introduced into the U.K in 1893. Europe’s largest wild herb and can grow up to 5 metres tall. Usually found along riverbanks and on waste ground. It is a very large and impressive plant. Giant Hogweed has a hollow green stem with red / purple spots and spiky hairs. Its leaves are dark green rosette shaped with spiky tips and can be up to 2.5 metres long on its lower levels. The flowers are white and found in one large umbrella head up to 1 metre across and will produce up to 50,000 seeds which are viable for up to 15 years. This long seed viability makes short term control impossible once seed has been produced. Giant Hogweed is a biennial plant, it grows from seed in year 1; flowers and sets seed in year 2.
The sap of Giant Hogweed is phototoxic and is be very dangerous and causes severe skin burns which can reoccur over several years when the skins is exposed to sunshine and ultra violet rays. It can lead to blindness if contact with the eyes occurs.
Due to its very large leaves, it can block out up to 80% of available light, reducing the population of native species. During winter flood, this lack of native plants can lead to erosion on river banks. Its seeds spread very easily through footwear, water courses, by wind and in car tyres. Long seed life can lead to a very long eradication process.
Giant Hogweed can be controlled by manual means such as digging out; cutting annually (before setting seed) below ground; grazing.
Herbicide application is also an effective method of eradication suitable methods include spot treatment with a knapsack applicator and stem injection.
Listed on schedule 9 section 14, it is an offence to deliberately cause it to grow in the wild. Environmental protection act, Duty of care 1991. All waste material contaminated with giant Hogweed is controlled waste.
These are some of the other invasive plant species, both terrestrial and aquatic, if you believe that you may have a problem plant please do not hesitate to contact us and we can arrange a survey.
Cotoneaster (various species), Rhododendron, Cherry Laurel, Japanese Rose, Giant Rhubarb (Gunnera), Virginia Creeper, Montbretia, Yellow Azelea, Sea Buckthorn, Buddleia.
Canadian Waterweed, Australian Swamp Stonecrop, Parrot’s Feather, Nuttall’s Waterweed, Floating Hyacinth, Water Lettuce, Water Primrose, Fanwort/Carolina water shield, Water Fern.