Plant in Focus: Oxalis triangularis
The genus oxalis is a deciduous edible perennial plant in the Oxalidaceae family and is native to tropical South Africa and South American where they’re most commonly conceived as a weed. In Western horticulture however, they’re perceived as ornamental plants due to their delicate bell shaped flowers and dainty butterfly-like leaves which beat; opening and closing as the plant reacts to changing levels of light. Perhaps it is because of their gentle, almost whimsical architecture and form that oxalis has found itself as a popular houseplant. One could also argue that their surge in popularity also stems from the fact that they are delightfully adaptable and easy to care for, withstanding longer bouts of neglect by dying back. At this point you may start to panic, thinking you’ve (maybe yet again) killed another one of your houseplants. But fear not! Oxalis grow from corms, oval in appearance and bulb like in make up, meaning that the plant will happily send up new stems after a little more TLC and a good watering. A quite side note- you may find that your oxalis will naturally die back in the winter, even if you continue your care routine.
Prefers bright, indirect light but is happy to bathe in some direct light for either part of the morning or afternoon. Be sure to protect the oxalis’ delicate leaves from direct light in the warmer months by moving it slightly further way from the window or light source. If you fail to protect it from the sun, its purple leaves will scorch, turning brown and crispy. If you’re keeping this plant outside in the spring and summer, ensure to place it in partial shade.
This plant is fairly adaptable, meaning it will be happy and thrive when settled in both warmer and cooler temperatures when inside all year round. However, if you decide to grow oxalis outside, do not put it out. until after the last frost, and bring it back inside just before the first frost of winter. Oxalis is not frost resistant.
Like most plants, the amount of water you have to give them depends on the time of year, temperature and size of pot. Ensure that you water your oxalis well and allow the top 2 inches/ 5cm of soil dry out between waterings. If the soil is left or is continually left to dry out, you may prompt it to become dormant and die back.
During the spring and summer months feed once a month with a diluted houseplant fertiliser.
Repot during spring into a pot that is around 2cm wide in diameter. Pot with a potting mix which has good drainage, yet suitably retains water. We suggest you mix two parts coir, one part all purpose (peat free) compost and one part horticultural grit or sand.
This can be done by division or seed.
What goes wrong
Leaves turn brown and crispy.
Too much direct light. Check to see if your plant is experiencing long periods of time in direct light. If this is the case, move slightly further into the room away from the window.
Leaves lose colour, has long straggly stems and doesn't flower.
Plant isn't receiving enough light. Gradually move to a brighter spot where it can get brighter indirect light, with some direct light. Avoid south facing windowsills and east facing windowsills are safer than west facing as the sunlight is weaker in the morning.
Tubers are in too much light or root mealy bug.
Check plant's conditions. If there's white woolly patches on the roots swirl them in insecticide or rubbing alcohol and allow to air dry to 2-3 days before repotting into a fresh potting mix. Do not water for two weeks.
Leaves become limp, dry up and fall off.
Too dry. Soak the plant in water for up to an hour, drain and then increase the regularity of your watering routine.