Northwest Native “Shamrock”: Meet the Redwood Sorrel

With St. Patrick’s Day approaching, we thought it would be a good time to highlight a beautiful Northwest native plant that resembles a shamrock. Oxalis oregana, or redwood sorrel (also known as Oregon oxalis), is a small herbaceous perennial that blooms from early spring through summer. They’re native to the U.S. West Coast, from British Columbia south to California.

In Washington state, you may encounter them as thick, lush carpets of green in coastal forests, such as those in Olympic National Park.

Oxalis oregana has three shamrock-like, heart-shaped leaflets with a deep green color. The plants most commonly portrayed as shamrocks are:

• Oxalis acetosella (wood sorrel)
• Trifolium repens (white clover)
• Medicago lupulina (black medic)
• Trifolium minus (hop clover)

Our native redwood sorrel spreads by creeping rhizomes (horizontal rootstalks) and can spread quickly once established. It’s well-suited for partial shade or deep shade areas, blooms in spring with white or pink flowers about an inch wide, and dies back in winter in colder regions.