Oxalis is the largest genus in the wood-sorrel family Oxalidaceae, comprising 800 species out of the 900 known species in the family. The genus can be found throughout the world, except the polar areas; with the highest species diversity happens in tropical Brazil, Mexico and South Africa.
Oxalis is commonly known as wood-sorrels (named after its acidic taste reminiscent of the unrelated sorrel (Rumex acetosa), yellow-sorrels or pink-sorrels ( named after the color of its flowers).
Oxalis is annual or perennial. It has leaves that are superficially similar to those of some clovers. It produces spring and summer flowers that have five petals, which are usually fused at the base, and ten stamens. The petal color varies from white to pink, red or yellow. Oxalis fruit is a small capsule containing several seeds. Its roots are often tuberous and succulent.
Oxalis adenophylla (Chilean Oxallis or Silver shamrock) is an Argentinian and Chilean alpine plant. This clump-forming hardy perennial, 10 x 15 cm, develops from fiber-covered bulbs, is susceptible to rot in the winter in temperate zone, even though its cold-hardiness comes from the bulb's adaptation to freezing during dormancy. It has attractive grey-blue leaves, which consist of up to 12 radiating leaflets. In late spring, it bears purplish-pink flowers, each to 2.5 cm across, and with darker veining and throats. Oxalis adenophylla is useful for rock garden and can also do well as a house plant. Plant it in full sun and in well-drained soil.
Oxalis oregana (Redwood Sorrel or Oregon Oxalis) is native to the moist Douglas-fir and Coast Redwood forest of western North America from southwestern British Columbia, Washington, Oregon, and California. It is a spreading, hardy, herbaceous perennial with clover-like leaves, each with a grey mark and purplish underside. It bears cup-shaped, white, pale-pink or liliac flowers from late spring to mid summer; following by egg-shaped, hairy five-chambered seed capsules, and the seeds are almond shaped. Oxalis oregana is a good groundcover in shady area where the soil is fertile and moist.
Different species of Oxalis have different growing requirement. Porpagation is by seed in late winter or early spring and division in spring. Slugs, snails and rust are the pests and diseases that are known to attack the plant.