Cover crop use is increasing in the Pacific Northwest, but information is not readily available on the growth potential, biomass production, adaptability, and bloom period of warm season cover crop species and/or varieties for this region. A study was conducted in 2015−2016 at the United States Department of Agriculture – Natural Resources Conservation Service (USDA-NRCS) Plant Materials Center in Corvallis, Oregon to evaluate commercially available summer cover crops for the Willamette Valley of western Oregon. The replicated trial included ten warm- season species that were evaluated for emergence, canopy cover, vigor, pest and disease susceptibility, bloom period, plant height, and biomass production. Based on two years of data, buckwheat (Fagopyrum esculentum) and Sudangrass/sorghum-Sudangrass (Sorghum bicolor var. bicolor x S. bicolor var. sudanense) were shown to be particularly well adapted to our region and performed well for a variety of functions, including quick cover, weed suppression, biomass production, and bloom. This PDF is available through the NRCS.