Key Facts
- Native to moist coastal forests of the Pacific Northwest
- Low growing perennial that forms mats on the forest floor
- Leaves are trifoliate and clover like and close at night or in low light
- Flowers are delicate and usually pale pink to white in spring
- Prefers cool shaded sites with humusy, consistently moist soil
- Spreads mainly by creeping rhizomes and can form dense colonies
- Contains oxalates that produce a sour taste and can cause upset if eaten in quantity
- Useful as a native groundcover in shade and woodland gardens
Redwood Sorrel (Oxalis oregana) is a low growing woodland perennial that forms soft mats of clover like leaves and pale pink to white flowers in spring. It works as a native shade groundcover where cool, humus rich soil stays evenly moist but can spread into dense colonies via creeping rhizomes.
Identification
Leaves are trifoliate and clover like, typically 2 to 6 inches tall overall. Leaflets close at night or in low light. Flowers are delicate, usually pale pink to white and appear in spring to early summer.
Best uses and where to grow
Use Redwood Sorrel as a native groundcover under trees and in woodland gardens where deep shade to part shade and cool, humus rich soil are available. It performs best in coastal and mild inland sites and is reported to do well in USDA zones 6–9, with local microclimate affecting winter survival and vigor.
Planting and spacing
Plant divisions or small patches where soil stays consistently moist and drains well. Expect a colony to spread roughly 6 to 24 inches across under favorable conditions, so give plantings room to expand or plan to divide and thin as it fills in.
Soil and watering
Redwood Sorrel prefers humus rich, acidic to neutral soil that remains consistently moist. Drier or compacted soils reduce vigor and prolonged standing water can cause rot. In low light the leaves stay turgid and attractive; in harsher light they scorch and the plant declines.
Bloom and seasonal care
Flowers typically appear in spring and may persist into early summer. After flowering keep the soil evenly moist and avoid heavy disturbance of the rhizome mat. In colder inland sites some winter dieback is possible; in milder coastal climates plants can remain evergreen.
Controlling spread and maintenance
Spread is mainly vegetative by creeping rhizomes and colonies can become dense. Control by thinning colonies, lifting and dividing patches, or installing edging to limit lateral rhizome growth. Hand removal works on small patches but be thorough because fragments of rhizome will regrow.
Propagation
Establish plants quickly by dividing sections of the rhizome. Seed is also possible but slower. Division gives an immediate rooted colony and is the fastest way to fill a planting site.
Toxicity and wildlife
Redwood Sorrel contains oxalates that give a sour taste. Small amounts are eaten historically and taste sour but larger quantities can cause stomach upset and may pose a risk to pets or livestock. Check with local poison control or a veterinarian for definitive guidance before allowing repeated access by animals.
Frequently asked questions
- How fast does Redwood Sorrel grow?
- Growth is by creeping rhizomes and colony expansion varies with moisture and soil fertility. Under favorable cool, humus rich conditions a patch can spread to 6–24 inches across over time.
- Is Redwood Sorrel toxic to pets?
- It contains oxalates. Small taste exposures are unlikely to be serious but larger ingestion can cause stomach upset. Confirm risk for your species with local poison control or a veterinarian.
- When does Redwood Sorrel flower?
- Flowers typically appear in spring and may persist into early summer, with exact timing varying by latitude and elevation.
- How do I stop it from taking over?
- Limit spread by giving plants only the space you want them to occupy, lift and divide crowded patches, thin rhizomes regularly or install landscape edging to block lateral spread.
Related Plants
