Oxalis purpurea aka Round Leaf Wood Sorrel

Oxalis purpurea is a small plant from South Africa. It is a perennial, which means it lives for years. Its native range includes the Cape of Good Hope. It belongs to Oxalidaceae, the wood sorrel family. Gardeners call it oxalis, wood sorrel, or sorrel. It once had the names Oxalis variabilis and Oxalis speciosa. It comes from a subtropical region. It grows from bulbs beneath the ground.

This plant has no stems and forms a low leaf patch. It reaches about 0.33–0.5 feet [0.10–0.15 metres] tall. Its listed garden spread is about 0.5 feet [0.15 metres]. Each leaf has three round parts called leaflets. These give the leaves the look of clover. Each leaflet is green above and purple below. A crease often runs through its middle. Running roots and new small bulbs, called offsets, help it spread. In good conditions, plants can form groups called colonies. These can grow beyond the spread of one plant.

Single flowers rise above the low leaves in summer. Missouri Botanical Garden lists bloom from June to August. Each bloom has five petals round a yellow throat. The flowers can be deep rose, pink, violet, or white. They measure about 0.08–0.17 feet [0.025–0.05 metres] across. Their size helps them stand out against the small leaves. Both the blooms and the leaf colours add garden interest. The species name refers to the purple flower colour.

Grow it in soil that drains well, with moderate moisture. It accepts full sun or part shade. Some shade from hot afternoon sun suits it best. Missouri Botanical Garden lists USDA zones 9–10 for outdoor growth. In colder places, use pots you can move indoors. Plant bulbs in pots in spring. Move them outside after the last frost. Keep the soil evenly moist while plants grow. Water less in late summer as the leaves start to fade. Bring pots into a cool, dry place before frost.

Use it at the front of mixed borders where winters are mild. It also suits lawns within its hardy range. In colder gardens, use window boxes or other pots. Its low height keeps blooms close to the ground. Leave room for colonies where conditions help plants spread. Missouri Botanical Garden reports no major insect or disease problems. It rates the plant's upkeep as medium. In cold climates, care means moving pots indoors. It also means changing how much you water as leaves decline.