Home
House Plants
How to grow and care for Oxalis triangularis

❚ All products chosen independently by our writers. We may receive commission via affiliate links. See affiliates FAQs.

Oxalis triangularis in a pot. Jason Ingram

How to grow and care for Oxalis triangularis

Sue Fisher

Published: Tuesday, 23 July 2024 at 1:15 pm

All you need to know about growing and caring for Oxalis triangularis

Save

Plant Size:

Height: 20

Spread: 20

Oxalis triangularis, also known as false shamrock, is an eye-catching bulbous perennial that makes a long-lived and attractive house plant. Its dramatic foliage in shades of dark purple to burgundy-red creates a striking contrast to the blush-white flowers borne in summer. The leaves are three-lobed, hence the name of shamrock, which it resembles but is not related to.

Oxalis triangularis is native to Brazil. Its leaves have extra fascination because they open during the day and close at night.

Oxalis triangularis is borderline hardy, surviving in temperatures down to -3°C, so is suited to outdoor growing only in the mildest areas of the UK. Oxalis triangularis goes dormant in winter and regrows the following spring.

How to grow Oxalis triangularis

Grow Oxalis triangularis from bulbs and plant in spring or buy ready-grown plants in summer. Grow in pots or in the ground, either indoors all year or outside for the summer only.

Keep it watered and feed regularly during the growing season.

Where to grow Oxalis triangularis

Oxalis triangularis in a pot. Sarah Cuttle

Oxalis triangularis in a pot. Sarah Cuttle

Outdoors, site in sun or partial shade. Indoors, place in bright light but out of direct sunlight, which can scorch the leaves. It prefers a cool-to-warm room at a temperature between 15-21°C. Avoid draughts and wide fluctuations in temperature.

How to plant Oxalis triangularis

Planting false shamrock in a container display. Paul Debois

Buying dormant bulbs in late winter is the most economical way to grow Oxalis triangularis. Plant bulbs pointed-end up, 5cm deep, in pots of peat-free, multi-purpose potting compost. Or plant in fertile, free-draining soil outside, in late spring.

How to care for Oxalis triangularis

As growth develops, increase watering so that the compost stays evenly moist while taking care not to overwater. Ensure good drainage indoors by standing pots on saucers or trays of gravel. If growing in pots on a hard surface outside, raise the pots just off the ground so any surplus water can drain away. Feed every 3-4 weeks during the growing season with a liquid fertiliser that is high in potassium.

In autumn, Oxalis triangularis starts to die back in preparation for winter dormancy. Reduce and then eventually stop watering the plant, keeping the compost almost dry over winter. Start watering again in early spring to encourage new growth.

If growing outside in pots, move to a greenhouse, polytunnel, conservatory or porch for winter.

How to propagate Oxalis triangularis

Propagate Oxalis triangularis by division, while dormant, in late winter. Split clumps of older, established plants into smaller clumps of bulbs and replant them at the same depth as they were growing previously.

Pests and diseases

Oxalis triangularis is trouble-free to grow, given the correct growing conditions. Take care not to overwater, which causes plants to weaken, rot and die.

Advice on buying Oxalis triangularis

The species Oxalis triangularis is widely available. Less commonly available are the several other named varieties with pink or yellow flowers, which are usually sold as pot-grown plants only
Bulbs of Oxalis triangularis are available to order in winter or early spring from bulb suppliers and online nurseries
Always check bulbs for signs of mould before planting and plants for signs of damage or disease

Where to buy Oxalis triangularis online

Don't miss out this Winter

Enjoy expert advice on what to plant and grow this winter, and how to prepare your plot for the year ahead. Enjoy, 6 months for just £31.99

Subscribe now

Great gardening savings - straight to your inbox

Sign up to the BBC Gardeners’ World offers newsletter for exclusive deals, seasonal savings, and early access to special promotions.