How to Kill Hogweed

Updated February 21, 2017

Hogweed is related to the carrot, but it is classified as an invasive weed in may states and federally categorised as a noxious weed. It is a perennial that can continue to grow for up to 25 years if not eradicated. Although many people, including children, are attracted to hogweed by its enormous size, it emits a toxic sap that causes skin irritation if touched. Swift measures to eliminate hogweed as soon as you notice its presence are advised.

Put on a long-sleeved shirt, long trousers, gloves and eye protection before attempting to cut or kill hogweed plants. Any contact with the skin will cause rashes.

Locate the most sparse areas of infestation and dig up each hogweed plant using a shovel. Insert the shovel into the ground 6 inches away from the weed and dig straight down for 6 inches. Repeat to dig around the weed until you can lift the entire root system out of the ground.

Dig up as many hogweed plants as is possible and lay them in a location that receives bright sunlight. Let them dry for two to three days until they are completely brown and then throw them into a dustbin.

Wait until between March and early June and spray all smaller hogweed plants or areas of high growth with an herbicide containing the ingredient glyphosate or triclopyr. Spray the solution onto the weeds at the dosage recommended on the herbicide bottle, making sure to saturate the leaves and the stems.

Wait until July or August and re-examine the treated hogweed plants for green growth. If any green colouring is seen, reapply the herbicide.


Examine the site periodically for the next three years for signs of new hogweed sprouts. If new sprouts are seen, treat them immediately. Remove all clothing items and wash them immediately after removing or treating hogweed.


Do not cut hogweed with a string trimmer. Doing so may spray the sap onto your skin.

Things You'll Need

  • Long-sleeve shirts and long trousers
  • Gloves
  • Eye protection
  • Shovel
  • Herbicide containing glyphosate or triclopyr
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About the Author

Kimberly Johnson is a freelance writer whose articles have appeared in various online publications including eHow, Suite101 and Examiner. She has a degree in journalism from the University of Georgia and began writing professionally in 2001.