Yellow starthistle is thought to have been introduced into California from Chile during the Gold Rush. The weed readily took hold in California valleys and foothills, thriving in areas where the soil has been disturbed by animals grazing, road construction and wildland firebreaks. Today, yellow starthistle is a very common sight in vacant lots and fields, along roadsides and trails, in pastures and ranch lands, and in parks, open-space preserves and natural areas.
Capable of growing six feet tall and bearing flowers surrounded by inch-long spines, yellow starthistle reduces land value, prevents access to recreational areas, consumes groundwater and poisons horses. (Yellow starthistle isn't all bad. Beekeepers have found that it can provide an important late-season food source for bees.)
That's where goats can come in. Goats will eat yellow starthistle at all phases of growth, including the mature, spiny stage, when it is not palatable to other browsers and grazers.
"When goats eat yellow starthistle, they open up the canopy and allow sunlight to hit the ground," said Roger Ingram, UC Cooperative Extension natural resources advisor. "That allows other, more beneficial seeds to come up and grow. If you can get other plants growing in there, the competition will choke out yellow starthistle."
Landowners can raise goats themselves and direct them to areas of starthistle infestation with portable fencing, or they can lease the animals exclusively for vegetation control. More information on yellow starthistle management is available from the UC Integrated Pest Management Program.
View the video below for more information on goats' browsing preferences.