Oxalis triangularis are a beautiful plant to add to any collection, with their delicate stems and striking purple leaves.
Contrary to what you might think, this edible perennial is native to Brazil, and not Ireland – It’s green look-alike ‘regnelli’ is famous as a symbol of Ireland & Saint Patricks Day.
Anyway, on to the more interesting part of this page – some general care tips to keep your Oxalis (and you) happy.
Lots of bright indirect light will make this plant happy. If you give her too little, she’ll get leggy. If you give her too much, she’ll crisp.
Early morning direct light is also suitable, but avoid harsh afternoon sunlight.
Water thoroughly at every watering, ensuring that water passes easily through the pot.
It’s also important to flush the soil every 3 months or so, to remove excess minerals and salts, that build up over time. To flush the soil, put your pot under a tap and let the water run for 3-4minutes. Once the water has stopped dripping, replace it in its cache-pot or on its sous-coup. You may also water with distilled or bottled water, to avoid having to flush the soil as often.
Let the soil dry out slightly before watering again.
Always choose a pot with drainage, to avoid root rot. Oxalis are easily susceptible to this, and need good aerated soil. Choose a potting mix that is high in organic matter and perlite/bark. This gives your plant a good source of nutrients, but also allows oxygen into the mixture, allowing the roots to breathe.
Fertilise your oxalis monthly during the active growing months – spring through summer.
Its normal for the leaves to wilt and die back when its going into dormancy. Once you see this process start, stop fertilising.
A water-soluble fertiliser is recommended, and its always important to read dosage directions on the product label, to avoid incorrect dosage and root burn.
Oxalis can be propagated in two ways – seed and division, although the latter is far more common.
To propagate via division, remove the plant from the soil, and separated the smaller, outer rhizomes from the main cluster. This is best done just before the end of dormancy, so your new rhizomes are ready to start growing shortly after separation.
Just like any other houseplant, oxalis are prone to pests and disease.
The main cause of plant death is root rot (from overwatering). To avoid this, ensure your soil is well draining and you don’t water too often.
Mealybugs and Spider mites are also common pests that can damage your oxalis.
See my blog post on pest control here, for tips on prevention and control.