Working with Willamette Riverkeepers, Benton SWCD and volunteers held manual weed pulls on the Corvallis to Albany stretch of the mainstem Willamette River on June 20th, 24th, and 25th, 2015. Marci Krass and Kate Ross Kuthe of the Willamette Riverkeepers along with their intern Gilbert Hamilton provided canoes, life jackets, paddles, and gloves for the trip. Crystal Durbecq of Benton Soil and Water Conservation District provided aquatic weed ID guides and information about both native and non-native aquatic plants along the way. The focus plant for the weed pulls was Ludwigia.
Ludwigia is an invasive perennial plant that floats and forms mats on the surface and in the water up to ten feet deep. It is considered a pest plant because it clogs waterways, impedes recreation, and outcompetes native plants. It is important to pull every piece of the plant out of the water when hand pulling Ludwigia, because a new plant can propagate from just a piece of the stem or from a leaf, and floating roots will resprout.
The volunteers that attended the weed pulls included concerned citizens from areas around the Willamette River from Portland to Corvallis. Another group that attended the weed pulls were the Teen Weed Spotters. The Teen Weed Spotters are students from grades 10 to 12 who are learning about the environmental and economic impacts of weeds and discuss and practice techniques for prevention, maintenance, management, and control. Teen Weed Spotters is a cooperative program of Benton SWCD and OSU Extension 4-H, Benton County.
If you see Ludwigia, report it to the Oregon Invasives Hotline. There is a native Ludwigia, but it has little green flowers in the leaf axils instead of the invasive plant’s big yellow flowers.