Oxalis pes-caprae

Oxalis pes-caprae_buttercup oxalis_ JM Di Tomaso
Photo courtesy Joseph DiTomaso

Common names: Bermuda buttercup; buttercup oxalis; sour grass

Oxalis pes-caprae (buttercup oxalis, Bermuda buttercup, yellow oxalis) is a low-growing perennial (family Oxalidaceae) found along the coast of California, in the Coastal Ranges, and in the Sacramento Valley. Buttercup oxalis occurs in coastal dunes, scrub, oak woodlands, gardens, turf, urban areas, orchards and agricultural fields. Buttercup oxalis was introduced as an ornamental landscape plant from South Africa. Although buttercup oxalis does not produce seeds, it is difficult to control because of its ability to form many persistent bulbs. Cultivation may be an effective control if carried out when the plants are just beginning to flower.

Cal-IPC Rating: Moderate

Cal-IPC Assessment

Plant Assessment Form - Information gathered by Cal-IPC on the impacts, rate of spread, and distribution of invasive plants in California. Does not include management information.

Weed RIC Management Notes

  • Management Notes - Information on management techniques and effectiveness from the University of California Cooperative Extension’s Weed Research & Information Center.

Cal-IPC Newsletter Articles

Cal-IPC Symposium Presentations

  • Stringer, L. and M. Heath (2011). Comparison of four herbicide treatments on Oxalis pes-caprae. Cal-IPC 2011 Symposium. Tahoe City, CA, California Invasive Plant Council.
  • Giessow, J. and P. Zedler (1996). The effects of fire frequency and firebreaks on the abundance and species richness of exotic plant species in coastal sage scrub. California Exotic Pest Plant Council Symposium '96. San Diego, CA.

Other Oxalis pes-caprae Information

  • CalPhotos - Images of plants taken mostly in California.
  • Calflora - See the distribution of this species on Calflora's map of California.
  • CalWeedMapper - Distribution information with ability to determine regional priorities.
  • Jepson Online Interchange for California Flora - Information on taxonomy, biology, and distribution from UC Berkeley's Jepson Herbarium.
  • USDA PLANTS Database - Federal database with information on identification and distribution, and links to websites in individual states.
  • Bugwood - National database from the Center for Invasive Species and Ecosystem Health at the University of Georgia.