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Benton County CWMA Recent Garlic Mustard Detection in Benton County

Garlic mustard detected in Benton County; report sightings at oregoninvasivehotline.org or call 1-866-INVADER.
Garlic mustard detected in Benton County in July 2025. Photos by Cierra Dawson.
Garlic mustard detected in Benton County in July 2025. Photos by Cierra Dawson.
A person holding a stem with green leaves and small white flowers in a garden.
Green ground foliage with round, serrated leaves; some dead, brown leaves interspersed.
Green leaves and vegetation surrounding a fallen log in a forest setting.
Green leaves with a few dried, yellow leaves on the ground. Some twigs and debris are present around the plants.
Garlic mustard detected in Benton County in July 2025. Photos by Cierra Dawson.
A person holding a stem with green leaves and small white flowers in a garden.
Green ground foliage with round, serrated leaves; some dead, brown leaves interspersed.
Green leaves and vegetation surrounding a fallen log in a forest setting.
Green leaves with a few dried, yellow leaves on the ground. Some twigs and debris are present around the plants.

At the beginning of July, Oregon Department of Fish and Wildlife staff were conducting routine monitoring on a parcel and stumbled across an undocumented patch of garlic mustard in Benton County. A report of this sighting was made on the Oregon Invasives Hotline, which triggered both Oregon Department of Agriculture (ODA)'s and Benton SWCD's noxious weed radar. While garlic mustard has been documented in the county in the past, it is generally considered to be more pervasive in counties north of us near Portland and uncommon to occur this far south. The sighting has been confirmed and is located on private property south of Corvallis just outside of Monroe. The landowner has been notified, and Benton SWCD, ODA, and Greenbelt Land Trust will be working collaboratively going forward to try to mitigate the spread of this patch. We currently believe it spans about an acre. This is an excellent example of quick collaboration and action that can only happen through cooperation and partnerships!

You can read additional information from ODA about this noxious weed here.

If you see this plant in Benton County, please report it to the Oregon Invasives Hotline. 

For further questions/inquiries, please email Cierra Dawson at cierra@bentonswcd.org