Category Archives: Invasive Weeds

Garlic Mustard Dumpster

a field of invasive garlic mustard is flowering

EMSWCD is once again providing a dumpster for disposing of pulled and bagged garlic mustard. The dumpster is located on the Historic Highway, in front of the ball field across the street from the Corbett Water District.

The dumpster is marked clearly as GARLIC MUSTARD DUMPSTER. A tracking sheet is located below the dumpster – please fill out all of the information requested on the sheet so we can track how much time was spent pulling garlic mustard and where it came from. A dumpster will be provided each spring to help the community dispose of garlic mustard.

We are also allowing residents to dispose of tansy ragwort in this dumpster. Please only use this dumpster to dispose of garlic mustard and tansy!

Have any questions? Send an email to Chris    Learn more about pulling invasive garlic mustard

 

Remember: Re-visit pulled sites frequently to make sure no new garlic mustard plants grow and go to seed.

Managing invasive tansy ragwort weeds

Tansy weed (Senecio jacobaea) in bloom with cinnabar moth caterpillars feeding on it

It seems like tansy is everywhere this year, but its predators are not far behind…

Tansy is a dangerous pasture weed because it is poisonous to livestock, causing liver damage when ingested.

What to do if you have tansy on your property

We don’t recommend mowing, which can extend the life of the plant beyond its normal two years and increase the chance that it could get into hay. Some plants are beginning to seed now, so mowing now is more likely to spread infestations further.

Your best bet for removal is pulling or digging. Unfortunately, the ideal time to pull the plants was between May and June, after they bolted but before they flowered. At this point, it may be better to wait until next year to remove them. If you need to pull it this year, you’ll want to bag it and dispose of it in the trash so the seeds don’t spread. When left alone, the seeds disperse by wind, but they only travel an average of 10 feet from the plant, so letting it go to seed in place will not cause rapid spread.

For residents in the Corbett area, we also offer a dumpster to dispose of tansy (and garlic mustard) every year, usually beginning in April. Find out more here.

Tansy predators making a comeback
Tansy has two main biological controls (“biological controls” in this context means natural predators that help control invasive plant or other pest populations) that feed on it when it starts to spread: the cinnabar moth and the flea beetle. Cinnabar moth caterpillars have been spotted around the district (see photos) this summer. Although less visible, it’s really the flea beetles that do most of the work, attacking the root crown, leaves, and leaf stalks during the rainy season. We will be looking for the small, golden flea beetles come October.


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Getting rid of invasive garlic mustard!

patch of invasive garlic mustard, flowering

Garlic mustard is a very invasive, fast-spreading weed, and Multnomah County has the worst infestation of it in Oregon. The roots produce a chemical that is toxic to other plants, and it can grow in most soil types. It can also grow in full sun or full shade, making it a threat to a wide variety of our native plants and habitats. You can help get rid of it, though – read on for some important tips about pulling up and getting rid of garlic mustard.

Many other plants are often mistaken for garlic mustard, especially before the flowers come up. Control is easiest when garlic mustard plants are in bloom (usually beginning in April), unless you can easily identify the rosettes (leaves) of the plant. Hand removal can be a successful technique in small patches that can be visited often and re-pulled frequently. Learn how to pull up garlic mustard and see more photos after the break! Read more

Learn to identify invasive weeds!

garlic mustard, an extremely invasive weed

Help prevent the spread of invasive weeds by learning how to identify them yourself! This workshop is for anyone interested in protecting Oregon’s natural areas from invasive weeds – no previous experience required! We have two Weed Watchers trainings this Friday and Saturday.

You will learn how to identify, look for and report new invaders before they become a problem. See live and preserved weed specimens, learn how they spread, and about the problems they bring. You can help prevent that next nasty weed from getting established!

Register for our May 16th workshop Weed Watchers   Register for our May 17th workshop Weed Watchers