Mowing and subclover plantings suppress yellow starthistle

Abstract

Yellow starthistle, a plant pest introduced to California in the mid-1800s, has infested more than 10 million acres and continues to spread. Vegetation managers, producers and land owners are searching for control methods that are compatible with their various land uses. Mowing and competitive plantings are two options that can be useful in yellow starthistle management programs. Timing is important. If mowing occurs too early, yellow starthistle can take advantage of the reduced competition for space, light and water. If it is done too late, large quantities of seed will disperse and replenish the seed bank. There were weed control benefits from planting subterranean clover as a competitive plant in combination with mowing, but the tested varieties declined substantially.