Oxalis triangularis, Purple Rain Shamrock,

Oxalis triangularis, Purple Rain Shamrock,

Oxalis triangularis, commonly called false shamrock, is a species of edible perennial plant in the Oxalidaceae family. It is endemic to Brazil. This woodsorrel is typically grown as a houseplant but can be grown outside in USDA climate zones 8a–11, preferably in light shade.

The deep maroon leaves are trifoliate, like species in the clover genus Trifolium which are commonly called shamrock, hence the name “false shamrock”. An interesting feature is that the leaves close like an umbrella at night (See the timelapse video below). The white or pale pink five-petalled flowers also close at night.

Growing to 50 cm (20 in) tall and broad, the subspecies O. triangularis subsp. papilionacea, the purpleleaf false shamrock, is hardy in mild and coastal areas of Britain, down to −5 °C (23 °F), and has won the Royal Horticultural Society’s Award of Garden Merit.

The leaves of O. triangularis move in response to light levels, opening in high ambient light (in the day) and closing at low light levels (at night). This movement is not due to growth and is instead powered by changes in turgor pressure in cells at the base of the leaf. It is an example of photonasty.

Incredibly long lived, oxalis triangularis often become “heirloom plants” passed down from generation to generation

oxalis triangularis has developed a natural toxicity to protect it from foraging animals. This is a plant that bites back, so take care with pets and small animals.

Poisonous for pets: Toxic to cats and dogs.








Species:O. triangularis

Binomial nameOxalis triangularis
A.St.-Hil.Synonyms Oxalis regnellii

Date Planted

replanted May 10, 2018

Purchase Info

Spring 2018 Belgium

Diseases and Problems


Temperature: Temperature: Between 60 – 70°F (15 – 21°C) “no higher than 75°F – 24°C” seems to be the ideal temperatures during the day and no lower than about 55°F (13°C) during the night.
Light: A good shaded spot within the home from direct sunlight is ideal. Sat back from a window in a bright room is suitable, but if the room is more north facing, place much closer to the window.
Watering: One of the worst things you can do with bulbs is over-water, which rots the bulb. Allowing the soil to begin to dry at the top is a good measurement of when to water again. Remember to stop watering if the plant becomes dormant.
Soil: Most potting mixes that drain well, which are also well aerated will do the trick.
Fertilizer: A diluted liquid fertilizer is helpful to use during the growing period. Feed once every 1 or 2 weeks. No feeding is required during dormancy.
Re-Potting: You may want to re-pot your plant once every 1 – 2 years (during dormancy period) and use the same pot or move up a size bigger, unless your removing offsets which reduces the size of the plant “or keeps it to the same size”.
Humidity: Average room humidity is fine.
Propagation: If you want to propagate your oxalis triangularis you’ll find it’s best to do this towards the end of it’s dormant period (I would do this after 2 weeks of dormancy to be sure of timing). The bulb will have to be removed from the pot and then you may remove the small bulb offsets which are re-potted to produce new plants. Be patient with the new plants and expect them to appear a little later than the main plant.


Oxalis triangularis bulbs look like small, immature pinecones. When planting a container for indoors, go ahead and crowd your bulbs, spacing them just an inch apart for a full look fast. Just poke the bulbs into the soil – any way up is right. Water lightly just once every couple of weeks until new growth appears. In about 6 weeks from planting, your new purple shamrocks will begin to appear, and will fill in to become lush and full soon after. Weekly watering should be light. Too much water will send the plant back into dormancy.

oxalis triangularis occasionally go dormant, looking like the entire plant has died. This happens generally during the summer every 2-7 years when the plant is indoors. Stop watering and let the soil thoroughly dry. In a few weeks, you will see a new leaf emerge. That is the time to resume watering. Soon, your purple shamrocks will be lush and full again.

Indoor care

They require bright or direct sunlight supplemented with a cool indoor temperature of ~15 degrees Celsius (~60 degrees Fahrenheit). They can tolerate higher indoor temperatures but will go into dormancy prematurely and/or begin to take on a “tired” appearance if temperatures go above 27 degrees Celsius (~80 degrees Fahrenheit) for prolonged periods of time. Use average potting soil with good drainage and allow the surface soil to dry out between waterings. Mature False Shamrock plants are cut back to the soil every 3–5 years in early summer or during the dormancy period. Young plants are cut back to the soil every year in early summer or during the dormancy period, until they reach maturity.


Oxalis triangularis are plants that grow from corms, and their propagation is done by division of the corms. Like other corms, the oxalis go through dormancy periods on a regular basis; at the end of such period, the corms can be unearthed, offsets cut and replanted.