Cooperative Weed Management Areas

As stewards of over 3.2 million acres of public and private lands the Rogue Basin, the Jackson and Josephine County Cooperative Weed Management Areas (CWMAs) engage in the control of invasive plants in riparian zones, floodplains, and wetlands throughout the Rogue Basin. Riparian areas are not truly restored if diverse native plant communities degrade over time from an invasion of aggressive non-native species.

The two CWMAs, who work together, are a group of state and federal agencies, local governments, tribes, nonprofits, community organizations, and individuals who have joined their efforts to combat invasive species in the Rogue Basin. Coordinated by RBP staff, the CWMAs provide a forum to share information and resources, collaborate on planning, and cooperate on invasive species management.

Thanks to our funding partners–primarily the Bureau of Land Management and the Oregon State Weed Board– and expert applicators, our CWMAs helped public and private landowners monitor and control 410 acres of noxious weeds. With their persistence, the efforts are showing promise. Aggressive treatments– both hand pulling and, as appropriate, herbicide treatment– have limited infestations of several targeted species to relatively isolated patches along the mainstem Rogue River and within the Applegate watershed. The CWMAs have eradicated garlic mustard, a fast-spreading noxious weed, from four sites and reduced the density of mature plants at other sites.

In 2019, the noxious weed control program will continue to focus on garlic mustard and Dyer’s woad. Work on the garlic mustard sites will expand to include shiny geranium and perennial pepperweed. Surveys for aquatic weeds in the Basin’s lakes and reservoirs will also continue.

For more information on invasive weed control in the Rogue Basin, visit:


Weed of the Month: Rush skeletonweed

Rush skeletonweed (Chondrilla juncea). “Chondrilla” is an old Greek word for, generically, a plant resembling chicory. Rush skeletonweed belongs to that large aster subfamily which, characterized by ligulate inflorescences (that is to say, uniform florets each featuring a long strap-shaped petal) and milky sap, includes such familiarly weedy members as...
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Weed of the Month: Himalayan Blackberry

Himalayan Blackberry has spread to all parts of the Rogue Basin except at the higher elevations. Where it used to be found only along ditches and streams, now it appears even in drier upland areas. It grows quickly, forming an impenetrable thorny thicket. Large berries appear in late summer which...
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Weed of the Month: Shiny Geranium

Shiny geranium (Geranium lucidum) is an annual weed native to Eurasia. This species is a recent invader in Oregon with a strong foothold in the Willamette Valley. Shiny geranium was first documented in the Rogue Basin in the mid 2010’s and populations have since expanded along the Rogue River corridor...
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Weed of the Month: Yellow Starthistle

In pastures, roadsides, oak woodlands, meadows and over buried pipelines and under power lines, the spiky yellow flowers and frosty vegetation of nonnative invasive yellow starthistle (Centaurea solstitialis) is a familiar sight in the Rogue Basin. This noxious weed is native to the Mediterranean and was first introduced to the...
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Weed of the Month: Salt Cedar

Salt cedar, also known as tamarisk, is an invasive shrub or small tree that is found across the American West. Populations are prevalent along waterways east of the Cascades, but last week members of the Applegate Partnership & Watershed Council identified it along the mainstem Applegate River near Provolt. The...
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Weed of the Month: Knotweed

Japanese and giant knotweed were introduced as ornamentals to North America in the 1800s and soon escaped to become invasive weeds. These tall, fast-growing herbaceous perennials are also known as false bamboo, due to their similar appearance. The knotweeds thrive in moist areas and are highly invasive along streams and...
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Let’s Pull Together

A silent invasion of weeds is taking over some of our beautiful Oregon landscapes. The Jackson & Josephine Cooperative Weed Management Areas are sponsoring three educational community events in Cave Junction, Grants Pass, and Eagle Point this spring. Join us with friends, family, and fellow nature enthusiasts as we pull...
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Weed of the Month: Dyer’s Woad

Dyer’s Woad (Isatis tinctorial) is a problematic, invasive weed that has become established across thousands of acres of western rangelands. Colonists first introduced the species to the eastern United States as an important source of blue dye. Alfalfa seed contamination has allowed the plant to successfully colonize pastures, rangeland, and...
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