Broadleaf woodsorrel makes a bright cheerful groundcover for shady areas.
There are more than 800 species of woodsorrels or "shamrocks." Most have clover-like leaves with three leaflets, sour tasting foliage (from the oxalic acid), and flowers and leaves that close up at night. Broadleaf woodsorrel has distinctly triangular leaflets, white or pinkish flowers with green throats, and grows from a thickened, bulblike taproot. It has no stems at all. Instead, the 8-10 in (20.3-25.4 cm) leaf petioles and flower pedicels arise directly from the rootstock. The leaflets are like equilateral triangles, about 2 in (5.1 cm) on a side and smooth bright green. The five-petaled, funnel-shaped flowers are about 1 in (2.5 cm) across and borne in loose, open clusters throughout the whole summer and fall. Broadleaf woodsorrel spreads readily from underground runners and forms a ground cover in moist, shady areas.
Woodsorrels occur naturally on all continents. Broadleaf woodsorrel is native originally to Mexico, Central and South America, and the West Indies, but is now established in much of the tropical and subtropical world, including Florida where it grows in disturbed, moist and shady woods. In some situations broadleaf woodsorrel can be a troublesome weed, but it has not been condemned by the Exotic Pest Plant folks.
Culture Light: Broadleaf woodsorrel grows well in partial shade. Moisture: Broadleaf woodsorrel grows best in moisture-retentive soils with lots of organic matter. Hardiness: USDA Zones 8 - 11. Propagation: Broadleaf woodsorrel spreads by producing little bulbils on short underground runners from its main bulb. New plants then come up from the little bulbils. To get new plants, just divide off the new bulbils.
The broadleaf woodsorrel's flowers close at night and during cloudy weather.
Broadleaf woodsorrel is a great groundcover in moist, shady areas. It can be invasive in such situations, but if you have just a small area that is suitable, then this shamrock is a good choice. It won't take over a sunny and dry lawn.
Many of the Oxalis species are invasive garden and greenhouse weeds. Some are cultivated as container and garden ornamentals. One (O. tuberosa) is grown in the high Andes for its edible tubers called ocas.