Jointed Goatgrass

Jointed Goatgrass is a Class C Weed. The Class C status allows counties to enforce control if locally desired.Other counties may
choose to provide education or technical consultation.

History & Biology

Jointed goatgrass (Aegilops cylindrica Host) is a winter annual grass native of southern Europe and western Asia. Jointed goatgrass is generally found in areas of 10 to 20 inches of annual rainfall and in elevations of 800 to 4,000 feet. It is closely related to wheat and the two species share a similar genome (D genome). Wheat and jointed goatgrass can cross to form a sterile hybrid (photo 1). Jointed goatgrass is difficult to distinguish from wheat early in growth but can be distinguished when the spikes appear. Jointed goatgrass spreads exclusively by seed and is a contaminant of winter wheat. It is very difficult to separate jointed goatgrass segments from wheat seed due to similar size and weight. A jointed goatgrass plant can produce up to 100 spikes, 1,500 joints and up to 3,000 seeds in a single plant. Approximately 75 to 80 percent of the spikelets contain 2 seeds and about 20 to 25 percent of the spikelets contain 1 seed. A very small percentage of spikelets contain 3 seeds. The leaves of jointed goatgrass are up to a ½ inch wide, and have evenly spaced fine hairs along the leaf edges and down the sheath opening. Stems can grow up to 4 feet tall and are tipped with slender, cylindrical spikes that appear to be a series of joints stacked on top of each other.

Photo by Phil Westra