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Medusahead, Elymus caput-medusae, was documented in California rangelands in the 1950's and has since invaded millions of acres in California, Nevada and Oregon.  According to calweedmapper.org, Medusahead is currently in 48 of 58 counties and is in high abundance and spreading mostly unchecked.  Medusahead decreases biodiversity, grazing, wildlife habitat and recreation value of rangelands while increasing fire hazard. Although cost of Medusahead depends on what ecosystem service is of greatest concern, forage replacement cost is estimated at $22.50 per acre. Our study contributes to a toolbox of control options that land management professionals can use to tailor site-specific plans that are cost effective. We used glyphosate, a non-selective herbicide, applied in two doses and at three phenological stages, and examine the effects on Medusahead demography and on productivity of desirable forage species. Early applications killed all vegetation and produced little forage. A later application significantly reduced Medusahead without obliterating the season's forage. Cost of application of herbicide was $15/ac, including labor, fuel, herbicide and machinery. There were no effects of dose or date of application on the degree of control. Following herbicide application in 2008, treated plots had less Medusahead than controls. In 2009, both treated and control areas had less Medusahead than controls in 2008. This decline in the number of Medusahead plants in the control areas is attributed to a general reduction in Medusahead density in the experimental area.