Knowledgebase
Getting Rid of Giant Hogweed #760594
Asked July 08, 2021, 10:55 AM EDT
Clackamas County Oregon
Expert Response
Greetings,
Thank you for reaching out to Extension, and for exploring options outside of herbicides. Because of the risk of injury when handling this plant and the difficulty of distinguishing it from the native plant cow parsnip and poison hemlock, we recommend having a positive identification. If you want to take pictures and send it in here, we can help to positively identify. If you are already positive on the ID then great!
Giant hogweed can be eliminated using manual, mechanical, or herbicidal methods, or a combination of several. These include root cutting and mowing, and ongoing monitoring is important for any method. Descriptions of the methods can be found in these resources:
- https://wric.ucdavis.edu/information/natural%20areas/wr_H/Heracleum.pdf
- https://www.dec.ny.gov/animals/40961.html
Landowners who remove hogweed personally are also still REQUIRED to notify the Oregon Department of Agriculture of its presence, for tracking and surveying purposes. https://www.oregon.gov/ODA/shared/Documents/Publications/Weeds/GiantHogweedBrochure.pdf Report suspect sites to Oregon Department of Agriculture Noxious Weed Control Program <personal data hidden> o r c a l l 1 - 8 6 6 - i n v a d e r
Control where it goes
Prevent these plants from going to seed by managing them early, and avoid swapping new starts.
Control where it grows
- Dig: Digging up hogweed is effective, but the risk of injury from exposure to sap is substantial. Flowerheads are also clipped off mature plants, bagged and put in the garbage. Landowners who attempt to remove hogweed themselves should dress appropriately, though relying on professionals to do the removal is recommended.