Hazardia detonsa is a rare species of shrub in the daisy family known by the common name island bristleweed. It is endemic to three of the eight Channel Islands of California. This is a bushy shrub reaching 60 centimeters to 2.5 meters in height. It has densely woolly, hairy herbage of thick, serrated, oval-shaped leaves up to 14 centimeters long. At the ends of its whitish stems it produces bell-shaped flower heads each about a centimeter long. Each flower head has several rows of white woolly phyllaries and an open end revealing disc florets and longer protruding ray florets. The florets are yellow and may age to red or purple. The main threat to this species on Santa Cruz Island was the presence of feral Santa Cruz sheep. The sheep were removed, allowing the plant to begin its recovery there.