Yellow Woodsorrel
Oxalis stricta · C3 (Cool-season) herbaceous perennial (not a true grass)
Grass Family
Oxalidaceae (Note: This is a broadleaf herbaceous plant, not a member of the Poaceae grass family)
Grass Category
Invasive/Weed Grass (commonly found in turf and lawns)
Variety / Cultivar
Common wild-type Yellow Woodsorrel
Hardiness Zones
USDA hardiness zones 3-9; highly cold tolerant with summer-active growth cycles.
About This Grass
Commonly mistaken for clover, this plant features heart-shaped leaflets in groups of three. It produces small, five-petaled yellow flowers and explosive, upright green seed pods (capsules).
Blade Characteristics
Not professional grass blades; leaflets are heart-shaped (obcordate), light to medium green, and fold inward at night or under stress.
Root System
Shallow fibrous roots combined with slender, spreading rhizomes; forms a moderate thatch and spreads quickly across bare soil.
Growing Information
Origin Region
Native to North America; well-adapted to temperate climates globally
Growth Habit
Bunch-type with spreading rhizomes and stolons; forms dense, low-growing mats
Sunlight & Water Needs
Thrives in Full Sun to Partial Shade; prefers moist, fertile soils but is highly drought-tolerant once established.
Mowing & Maintenance
Maintenance involves removal rather than cultivation; tolerates low mowing heights (under 2 inches) and thrives on nitrogen-heavy lawn fertilization schedules.
Special Characteristics
Exceptional seed dispersal via explosive dehiscence; high shade tolerance; acid-tasting (oxalic acid) foliage; difficult to control in established turf.
Ecological Information
Native but often considered a weed; provides nectar for small bees and butterflies; seeds are eaten by various songbirds.