Hogweeds are also known as cartwheel flowers are perennial toxic and invasive plants that are very harmful to humans and the environment. Their toxic sap can cause extremely painful phototoxic burns and contact with the eyes can lead to blindness.

Hogweeds can commonly be found in lawns, fields, and nearby moving water. They are very tall, around 4-5 meters, have large, shiny, heiress leaves, white flowers, and a hairy stem covered in white hairs.

They can also be easily recognized through their dark purple-red blotches that can be found on the stem. 

Because of their large size, hogweeds need a lot of nutrients which they take up by competing with neighboring plants for natural resources through their dense root systems, leaving the other plants malnourished, causing them to die. 

One hogweed plant can produce from 20,000 to anywhere around 100,000 viable seeds which by wind can disperse 30 feet away from the plant but through water, they can reach longer distances.

It is essential to remove and prevent hogweeds from spreading because of their detrimental effects on the environment as well as human health. You can get rid of hogweeds manually, by using herbicide or mechanical equipment

Manual Weeding

Manual weeding commonly referred to as hand weeding can be effective for small areas with post-emergent weeds since they can be grasped and removed easily. However, it is not effective for perennial hogweeds, even if a small portion of the root is left on the soil the entire plant can easily regrow from it.

Removing giant hogweeds by hand is also extremely dangerous. The toxic sap of the hogweed is mostly located in the stem and can be relied upon by cutting or tearing the roots. 

Therefore, manual weeding is an insufficient way of eliminating giant hogweeds. 

Mechanical Weeding

Mechanical Weeding

Different machines can be used for weeding such as weed cutters or mowing machines. However, both of these machines should be used when the hogweed has not yet started to produce seeds. It takes around 5 years for the giant hogweed to grow and produce seeds so it is better to use machines in the early stages and remove the root manually using gloves. 

Chemical Herbicide 

To eradicate giant hogweeds it’s best to use a systemic weed killer since this type of weed killer will be absorbed by all parts of the plant including the roots, preventing the plant from re-growing the next year. 

chemical herbicides

Glyphosate and triclopyr are the most effective systemic herbicides for giant hogweed. Triclopyr weed killer works by interfering with the growth cells of the giant hogweed by mimicking a type of growth hormone and causes uncontrolled growth of the weed causing the plant to die within weeks. 

The herbicide should be sprayed when the plant is actively growing. It is essential to cut the flower heads of the giant hogweed to ensure that the seeds don’t start spreading.

Triclopyr should be sprayed repeatedly throughout the years so that the new developing weeds are eliminated for the long term.

Additionally, triclopyr is a selective herbicide meaning it will not harm your precious grass but will only remove weeds. 

Glyphosate is a non-selective systemic herbicide that will eradicate the weed to the root but will kill anything else that it comes in contact with. This type of herbicide is the only weed killer that is safe to use around water. 

Glyphosate works by preventing the weeds from producing necessary proteins causing the plant to die within weeks. Annual weeds die within days but perennial weeds like the giant hogweed take more than a week. 

The herbicide should be sprayed in late spring or early summer when the weeds are actively growing. It should be sprayed in calm weather conditions so that the weed killer has the necessary time to dry and start working.

It should also be sprayed throughout the year to make sure if any of the dispersed seeds are developing then they are taken care of as quickly as possible.


Giant Hogweeds can stay up to 15 years, thus a single treatment or method is not enough to remove them. They are highly poisonous weeds that can cause long-term damage to your skin, thus if your area is infested by it, it is important to remove them. The course of action to remove any type of weed involves identification, solution, removal, and then treatment.

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