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  • Giant hogweed appearance during the winter time

Giant Hogweed

Giant Hogweed Problem?

Not a problem for Japanese Knotweed Plus Ltd, Manchester!

Japanese Knotweed Specialists

The latest story from Japanese Knotweed Plus Ltd published in Manchester Evening News. Please click on the picture to read a full story

Please see Metro for more news from us.

Introduction to Giant Hogweed.

Giant hogweed (Heracleum mantegazzianum), part of the carrot family, it has widely spread throughout the UK, Europe, and the world. Attitudes towards the plant have become highly negative, supported by numerous stories and myths in the press and on the web. Hogweed can be very poisonous for humans & animals. It should be noted that a lot of varieties of well-established native species in the UK are poisonous too.

It was introduced to the UK in 1893 by the Victorians as an ornamental plant from the Caucasus Region and Central Asia. Now, it is one of the the most successful and dangerous plants growing in the UK. The plant is found along river banks, foot paths, in parks and other public areas. The wide spread of giant hogweed was facilitated by mainly ignorance in following strict recommendations on how to deal with the plant, this has contributed to the problem.

The hogweed family (Heracleum) accounts for around 70 varieties around the world, with an attractive appearance, giant hogweed plants can reach up to 15 feet high. The hogweed’s flowers are upturned umbrella in shape and can reach up to 3 feet in diameter, producing lots of pollen and nectar for honeybees and holding up to 80000 seeds. The leaves can grow to 6 feet across giving validation to the Latin name “Heracleum”.

After spreading throughout Russia, the leaves of the plant were added to soup or borsch in early spring. The shoots can be marinated and the leaves salted for further use. The leaves are dried after soaking in water or alternatively boiled to remove etheric oil. The roots, rich in sugar can be used to produce sugar. This plant is mainly found the in Caucasus region.

Giant Hogweed

Giant Hogweed leaf

The sap contains a photoactive toxic glucoside called furocoumarin and can be found in the leaves, stems & seeds. Contact with the sap on human skin followed by exposure to the UV light of the sun can cause serious burning and can even be lethal to children if the exposed area is sufficiently large enough. Interestingly, furocoumarins from other natural products such as celery, lime, coriander, carrots and parsley can make the skin sensitive to the UV fraction of sun light.

There is no legal obligation in the UK to remove or control the plants when it is growing in your garden. The plant is listed in the Schedule 9 Part 1 of the Wildlife and Countryside Act 1981 (as amended) beware, as spreading it in the wild is an offense and may be a subject to a penalty of up to £5000 or imprisonment.


Need help with managing Giant Hogweed on your land? Call for FREE immediate advice today

0161 8830 666

Giant Hogweed in the News.

In the Late Sixties of the XX Century

Giant Hogweed is not a novice in the mass media or other sources. After starting spreading noticeably in the sixties of the last century, the issues after the contact with the plant were recorded. For instance, The British Medical Journal reported on erythematous patches on arms, neck and legs of seven years old boy (13 July 1968, Correspondence from Janet H. Smellie from Liverpool).

In the Present Days…

BBC News (10/07/2015) reports of two boys in Bolton they were hospitalised after touching giant hogweed. NHS recommended anyone who comes into contacted with the plant should wash the exposed areas with water and soap then cover the area, thus, preventing the skin from direct sunlight.

***Warning: photographs*** Sunday Express (24/07/2015) tells a story about the first court case after a seven year old boy was severely affected by giant hogweed in a holiday park that was extensively infested with the plants.

Daily Mail
***Warning: photographs*** In Daily Mail, leading experts explains how dangerous giant hogweed is, he warns that the plants are now under the ASBO legislation.

Interestingly, in 1971, Genesis released an album Nursery Cryme with a great track “The Return of the Giant Hogweed”. Was this a prediction of further invasions of giant hogweed?

Removal Options of Giant Hogweed.

Giant hogweed is now often referred to as the most dangerous plant in the UK. Thus, strict safety measures must be implemented when dealing with the plant. We strongly recommend to contact dedicated contractors for removal of giant hogweed. Similar to Japanese knotweed, giant hogweed can be eradicated employing physical removal or by applying chemicals. As a company that specialises in the eradication of the range of invasive weeds, Japanese Knotweed Plus Ltd will eradicate giant hogweed by physical removing or applying chemicals, this is dependent on your particular case and circumstances and the time of season.

Cutting the Upturned Umbrella Shaped Flower before They Go to Seed

This is the most effective way to eradicate hogweed in small areas. However, this is also one of the most dangerous methods due to the possibility of splashing sap onto unprotected skin. If the correct time for trimming buds or flowers has been missed, special attention should be given to prevent the growth of new side-shoot umbrellas from the main rosette. Otherwise, once the plant has produced new umbrellas with flowers in their ovaries there will be a new generation of seeds, enough to restore the thickets of the plant.


Incineration is an effective way to destroy the maturing seeds and should be undertaken before the ripening process in the central largest umbrella is completed. The method requires care and accuracy as during burning, the umbrellas become flammable due to the oils in the seeds. The use of this method may not be permitted in residential areas.

Treatment with herbicide

Be aware the use of different types of approved herbicides is now only allowed by accredited specialists.

Note: since 26 November 2015, operation under the ‘Grandfathers Rights’ exemption,  is no longer allowed.

The operators applying professional herbicide must possess the UK recognised certification. This certificate is also required to purchase herbicide products.

Our professional operatives are obliged to contact the Environment Agency if treatments are to be carried out near to water ways.


Japanese Knotweed Plus Ltd

is accredited by City & Guilds to apply pesticides in land and aquatic areas using both spraying and injection techniques

Have a problem with giant hogweed? Call us now: 0161 8830 666


This is an effective way to destroy hogweed but only certainly before flowering repeated not later than 3-4 weeks after the first mowing. This technique is necessary to destroy all the generative shoots bearing inflorescences and the flowers accordingly. It is important to prevent hogweed from blooming and thus from forming new seeds. If hogweed was mowed only once in the middle of flowering it will only contribute to further proliferation of plants.


Precautions when Destroying Giant Hogweed. DO NOT

Mow hogweed between the end of flowering and early seeds set. This will not have the desired effect unless the crop will not be destroyed immediately after mowing. Any hogweed that has been cut down must immediately be removed in a heap and burned as it is one of the most available efficient ways to destroy the seeds.

Leave the cut down hogweed in situ. Even after it has been cut down, the main umbrella stem of the hogweed stores large supplies of nutrients enough to provide the seeds to germinate, ripen and give life to new plants.

Mow hogweed which is shedding seeds. This will just lead to a greater dispersion of hogweed. If the umbrellas with ripe seeds are cut especially in windy conditions it will help spread the seeds to new areas.

Deal with hogweed without protective clothing. Waterproof clothing is strongly recommended, as a plant sap may penetrate through ordinary clothes and touch the skin. If the sap in contact with human skin is not washed off within 24 hours it will result in burns if it then is exposed the light of the sun (strongly speaking, to the UV light that accounts 5% of the sunlight).


If You Are Accidentally Exposed to the Sap of Giant Hogweed, YOU MUST


Contact your doctor or nearest A & E department immediately.

Rinse the affected skin as soon as possible with cold running water and gently cover the area from UV light of the sun (note, UV light will not pass through ordinary window glass).

Use liquids containing alcohol for rinsing the affected areas (DO NOT RUB).

Not use any fixed bandage. You MUST carry out all the measures traditionally prescribed for skin burns.


Japanese Knotweed Plus Ltd

will help you get rid of giant hogweed through our safe and hassle-free treatment procedure

Call us now: 0161 8830 666