Short answer
Yes. Oxalis triangularis, often called purple shamrock or false shamrock, is widely grown as an indoor plant. It grows from small tubers or rhizomes and forms clusters of deep purple, triangular leaves that fold at night and open again in daylight. It is generally considered fairly easy, although its natural cycle of growth and rest surprises many new owners.
Light
Bright, indirect light suits it best. Too little light can cause leggy growth with leaves that reach toward the window, while strong direct sun, especially in summer, can scorch the foliage. A few hours of gentle morning sun is commonly considered fine. The leaves tend to follow the light, so turning the pot occasionally keeps it even.
Watering
Water when the top of the soil has begun to dry, then let excess water drain away. Soil that stays soggy can rot the tubers, while a plant allowed to dry out completely will wilt and may go dormant. There is no fixed schedule; frequency depends on pot size, light and temperature. Use a pot with drainage holes and a free-draining mix. If the plant looks droopy, check the soil before assuming it needs water.
Is it difficult to care for?
Most people find it easy as long as light and watering are reasonable. The most common worry is dormancy, which is normal and often mistaken for death.
Dormancy
Purple shamrock can die back and rest, sometimes after a period of heat, drought or simply after a stretch of growth. The leaves yellow and collapse. Do not discard the pot. Cut away dead foliage, reduce watering and keep the pot in a cool, lightly lit spot for a few weeks. Once new shoots appear, resume normal care. Some plants never fully go dormant, so this varies.
Can I put my Oxalis outside?
In summer, a shaded or partly shaded outdoor spot can work, with protection from strong sun and heavy rain. Hardiness depends on your climate. It is generally described as a plant for warmer regions, with frost damaging foliage and possibly the tubers. In cold areas, keep it in a pot and bring it inside before frost. Check local guidance, because some oxalis species spread aggressively in gardens in certain regions.
How long do Oxalis plants last?
With good care, the same tubers can produce new growth for years, so the plant is often described as a long-lived perennial. Individual leaves are short-lived, and the plant may look tired after flowering or dormancy. Dividing crowded tubers and refreshing the soil periodically helps.
Pet and child safety
Treat Oxalis triangularis as toxic if eaten. Oxalis plants contain oxalates, which can irritate the mouth and digestive tract and, in large amounts, may affect the kidneys. Oxalis species are listed as toxic to cats and dogs by animal poison organizations. Keep the plant out of reach of pets and small children, and call a veterinarian, poison center or doctor if any part has been eaten.
Related reading
For another seasonal houseplant that follows a growth and rest cycle, see indoor narcissus care.
FAQ
How often should I water oxalis? When the top layer of soil begins to dry, rather than on a fixed schedule.
Is it a good beginner plant? Generally yes, once you know about dormancy.
Why are the leaves closing? They fold naturally at night and in low light.