Knowledgebase

Getting Rid of Giant Hogweed #760594

Asked July 08, 2021, 10:55 AM EDT

Hello- I was wondering if I could get some advice on battling invasive Giant Hogweed. We do not use synthetic herbicides such as Roundup (which I hear is the most effective way to combat it), so I was hoping to get tips on how to combat it without the use of chemicals. We occasionally use agricultural vinegar mixtures on some weeds but wasn't sure if this was an effective method, or if digging out the roots is the best option. Any input is appreciated- thank you for your time!

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:

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. 
Warm Regards,  Replied July 08, 2021, 11:48 AM EDT

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