How to grow Oxalis triangularis

Commonly known as the 'False' or 'Purple' Shamrock. Oxalis triangularis is a bold coloured perennial bulbous plant native to Brazil. Its subtropical to tropical origins mean that it is a frost tender species and can only be grown as a bedding, conservatory or house plant in the cooler temperate regions of northern Europe.

Under favourable conditions you can expect Oxalis triangularis to reach a height and spread of between 10-50 cm. It is a winter dormant species with a mounded habit and striking purple leaves which emerge from the bulbs in the spring and lasting until the autumn. The white to pale-pink starry flowers appear over the summer.

Besides its excellent ornamental colour, is a great example of photonasty (non-directional responses to stimuli). This is expressed by the leaves opening out in high ambient light (as in during the day) and closing at low light levels.

When grown outside as bedding provide a sheltered, partially shaded position in a moist but well-drained soil

When grown under protection or has a houseplant indoors provide cool, frost-free conditions. Oxalis triangularis will requires a moisture retentive but well-drained good quality compost. Alternative you can make your own mix using of equal parts loam, leaf mould and grit.

Water moderately when in growth and apply a liquid soluble fertiliser monthly. When dormant over the winter months allow the soil to dry off more and just keep it just barely moist until new growth emerges in the spring. Repot every other October.


Main image credit - KENPEI - KENPEI's photo, CC BY-SA 3.0,

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