Control Where it Goes

Garlic mustard seeds move easily along streams and roads, and readily colonize disturbed soil. Hiking boots and vehicle tires are a well-documented means of spreading these seeds. So, you can keep new patches from popping up in your neighborhood yards and parks by cleaning your shoes after walking in areas of known garlic mustard infestations.

Control Where it Grows

• Dig: Digging up garlic mustard on private property can be effective, but requires weekly attention to catch new plants. Pulled plants will continue to flower and set seed. Be sure to bag them and put them in the garbage (not in your yard debris!!). BE SURE TO GET ALL THE ROOTS.  DON'T cut or mow. Leftover roots can regrow; cut plants might still flower and set seed.
• Treat: herbicide may not be necessary on small, local patches. The City of Portland treats mostly along roadsides, where miles of work prohibits effective pulling.
• Check: monitor the site every two weeks in spring, and especially years two and three after treatment, as any surviving seed takes its big opportunity to sprout!

Last Words

If you’ve got garlic mustard on your Portland city property, and there’s too much to pull, let us know. We may be able to help. You can download a Permit of Entry form, fill it out and return it by the end of April and we will treat garlic mustard on your property in May or June. If the treatment season has ended, we will add your name to our treatment inventory for the following spring.  All garlic mustard questions can be directed to Mitch Bixby with Environmental Services' Early Detection/Rapid Response Program at 503-823-2989 or mitch.bixby@portlandoregon.gov.