Gumweed (Grindelia squarrosa) is an erect annual, biennial or short-live perennial flowering herb that is a member of the sunflower family (Asteraceae). It is native to western and southwestern North America. G. squarrosa has alternate leaves with gland-dotted, toothed edges and gummy appearance. It produces numerous yellow flowers. G. squarrosa utilizes a deep taproot and an extensive shallow root system.
Toxic components
G. squarrosa is able to absorb high levels of selenium in certain soils, which can cause selenium toxicity. Most ruminants avoid the plant, however if there is little else to eat animals may consume the plant from hunger.
MANUAL CONTROL: Young plants and small infestations can be eliminated through hand-pulling, digging or hoeing. Frequent tilling of the soil can control mature plants. Mowing can help prevent seed production, but it may adapt to repeated mowing by forming a more prostrate habit.
