Giant hogweed

Giant Hogweed: How to identify, treat and get rid of this invasive species!

Delivering horrible burns and damaging native species, giant hogweed is among our nastiest invasive non-native species. But what can clubs and fisheries do to tackle it? Ian Doyle, our newly appointed Northern Environment Officer, has some great advice and success stories to share about ridding the banks of this unwanted invader!

Among all the invasive plants you might come across in Britain these days, giant hogweed has to be one of the most threatening of all. However, with the right approach, it can be controlled. But what exactly is it and where did it come from?

How to remove giant hogweed

Giant hogweed, pictured above, is a common invasive non–native species originating from the Caucasus Mountains in Southwest Russia and Georgia. Giant hogweed belongs to the Umbelliferae family, so named because of its umbrella-shaped flowers or umbels and is related to the wild carrot, cow parsley, and hemlock.

It is quite a sight to behold such an impressive plant and we have our ancestors to thank (or curse!) for its presence. Victorian High Society recommended that our large country estates should plant it near their entrance gates to cast an initial impression of wealth and grandeur.

Unfortunately, this species has now invaded our countryside, taking up habitat on our river banks and wherever it can stake a claim, damaging our bio-diversity. It deposits a phenomenal seedbank of thousands of seeds each year which can remain dormant until called upon by nature to regenerate and invade our native habitat.

These seeds can travel by river so will readily wash downstream or can be transferred by accident by not adhering to the CHECK CLEAN DRY message! Wet nets, stink bags, unhooking mats and dirty boots are a classic example of this.

Why is Giant Hogweed a problem?

Giant hogweed invasive species
Above: Young giant hogweed plants are easily missed.

Giant hogweed is a dominant, fast-growing species. It creates a monoculture that overshadows native riverine species, denying them the sunlight required for their photosynthesis. As a consequence of this and with further consideration given to the success of other invasive non-native plant species, such as Himalayan Balsam and Japanese Knotweed, native plant colonies are in decline. Some of these native plants have specific symbiotic relationships with certain insect species, which adds even further risk.

Giant hogweed dies back at the end of the summer leaving what can only be described as bare soil, (a naked, “scorched earth”), which when washed with winter rains increase the erosion of our riverbanks and the siltation of our rivers gravel runs. This then creates problems for everything from invertebrates to spawning fish, with excessive erosion also known to exacerbate flooding.

If damage to our native species and habitats wasn’t enough, this gruesome customer also has a sneaky weapon in its arsenal to protect it from damage. Its sap is a photo toxin which quickly takes effect when it comes into contact with our skin! This creates photosensitivity to UV rays and sunlight, resulting in serious burns that can re-occur for up to seven years when exposed to further sunlight!

What should you do if you get burned by giant hogweed?

If skin comes into contact with giant hogweed, treatment must be applied as quickly as possible. Rash like symptoms and red marks are common. These areas should be treated with cold water and soap, and kept as clean as possible. Do also keep any affected skin out of sunlight for the next 48 hours- because this can cause further inflammation. If you react further or an affected area remains sore, consult your GP about further treatment.

What can we do about giant hogweed?

There are four ways in which the angling community can get involved. Prevention is obviously better than cure, but we can all help in several ways:

• Firstly, learn how to identify it and stay away from it.
• Follow the CHECK CLEAN DRY message and STOP THE SPREAD.
• Report it. Local councils and angling club officials need to know of its whereabouts.
Take a photo of the plant from a safe distance and note your location. Inform your club official and contact the local council. Some councils have dedicated giant hogweed pages. Alternatively upload any images and their location to the iRecord website here or their app here.
• And lastly, manage it. Seek assistance where required or take the bull by the horns, get trained and get the required license.

For obvious reasons, giant hogweed must be dealt with using protective gear and extreme care!

Remember, it is extremely important to avoid contact with giant hogweed sap!

Sites should be carefully surveyed before using Strimmers or brush cutters which are unsuitable for use with giant hogweed due to the risk of sap coming into contact with your skin.

 Tap roots can be cut with a spade, flower heads can be gathered in a large plastic bag and disposed of as special waste, this kind of work must be carried out by specialists and is not recommended for general use, on a personal level I wouldn’t recommend that these techniques are used at all, giant hogweed really is that dangerous. My own preference due to the risk involved (and I should point out that I only carry out this work because I have the necessary qualifications), is spraying with Glyphosate during May when the plant starts its initial growth spurt, with revisits throughout the year.

Please don’t take such action alone or without consulting expert advice! If such treatments are carried out near water, this MUST be supported by the relevant agencies (the EA in England or NRW in Wales), who can provide consent to work or the required license.

Giant hogweed
Before spraying (above): giant hogweed has taken up a large area in this case!
 After spraying: The plants die back- and should be left to rot.


For further information on this species and others check out the Angling Trust website here for useful guides and ID pictures. Click here for a specific fact sheet for giant hogweed.

Applications to apply for herbicide use near water must be obtained from the relevant authorities.
Click here for applications in England

Click here for applications in Wales

For training information with regards to Weed Spraying PA1 PA6 and Pa6w, visit the Lantra and City and Guilds websites.

PLEASE REMEMBER: Giant hogweed is dangerous!

Should you come into contact with giant hogweed, you must wash the affected areas, avoid exposure to sunlight, and immediately seek medical advice.

All images are credited to the author some of which have been previously shared on

Ian Doyle
Northern Environment Officer
Angling Trust

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