Virginia Tech Weed Identification Guide

Yellow Woodsorrel: Oxalis stricta

Weed Description:  A perennial with trifoliate leaves and yellow flowers that is primarily a weed in greenhouses, container ornamentals, landscapes, turfgrass, and lawns.  Yellow woodsorrel is found throughout the United States.

Seedlings:  Cotyledons smooth, oblong, green.  Margins and veins on lower leaf surfaces of young seedlings are sparsely hairy.

Leaves:  Arranged alternately along the stem, long-petiolated, and divided into 3 heart-shaped leaflets.   Leaf margins are smooth but fringed with hairs.

Stems:  Green to pink, weak, branched at base, more prostrate than erect to 20 inches tall, varying from smooth to pubescent.

oxalis11-16.jpg (83631 bytes) Roots:  Long, slender rhizomes occur with a fibrous root system.

Flowers:  Occur in clusters that arise from long stalks at the leaf axils.  Individual flowers consist of 5 yellow petals that are 4 to 9 mm long.

Fruit:  A capsule that is cylindrical and pointed with flat sides, sparsely hairy. Each capsule is approximately 3/4 inch long.  Seed disperse from capsules by explosively ejecting up to 13 feet from the parent plant.

Identifying Characteristics:  A weed of greenhouses and ornamentals with leaves that are divided into 3 heart-shaped leaflets with small yellow flowers.  Yellow woodsorrel may be distinguished from Creeping Red Woodsorrel (Oxalis corniculata) by the presence of underground rhizomes versus the aboveground stolons of creeping red woodsorrel.  Also, creeping woodsorrel has a more prostrate growth habit and often has more reddish-purple leaves than yellow woodsorrel. oxast3-14.jpg (56281 bytes)