Oxalis triangularis
The striking purple leaves stand out amongst green indoor plants and it’s also photophilic, which mean that the leaves open and close in response to light. At night the leaves fold down and during the day they will open up. Have a look at some of these time-lapse videos.
Some plants are hard to take care of (I’m thinking of a Fiddle leaf fig) but the Oxalis Triangularis is fairly low maintenance.
Oxalis is a genus of the wood sorrel family and is well known for being an invasive weed in most gardens. However, there are some varieties of Oxalis that are perfectly well behaved and don’t spread all over the places, such as the Oxalis Triangularis. Oxalis is often referred to as a purple shamrock or false shamrock. Its history can be traced back to St Patrick in Ireland, even though the plant originated in Brazil.
How to care for it:
Light: Keep your Oxalis Triangularis in a filtered bright to medium light but away from direct light. It grows well in morning light (i.e. East window). It is fairly hard to burn since Oxalis grows outdoors, the glass in your windows will filter out a lot of the intensity of the light, however it will grow best when it’s away from direct sunlight. Take a look at some of the images at the bottom of this article for the lighting suggestions.
Water: Allow the soil to dry between watering, ensure the top 2cm of soil is dry before watering. The worst thing you can do with bulbs is overwater as it will rot the bulb. Expect to water about once every 2 weeks.
Soil: A well-drained potting mix works well. Use a standard Premium indoor potting mix. Oxalis will NOT grow well in overly wet soil but does like moist soil. Make sure your pot has a drainage hole.
Pot: Oxalis pots need to be deep, shallow pots will not work well. Avoid growing them in a pot with other plants as they can go dormant and their growth requirements are different. As the Oxalis tends to grow and bend towards the light, you should also rotate your pot every 2 weeks to ensure the foliage grows evenly.
Temperature: Standard indoor temperatures are fine. The ideal temperature is around 60-70°F(15-21°C). Temperatures above 75°F/24°C become problematic. At high temperature, the Oxalis will start to look ‘tired’ and may go into dormancy and drop all its leaves.
Fertiliser: I don’t find fertiliser necessary in new plants, but you could add every 2 months if the soil is older than a year. Premium potting mixes usually contain slow release fertiliser for at least 4 months worth.
Some interesting facts
Pests and disease
Rust: One of the most common diseases is rust, which appears in the lower half of the leaves. I encountered this on one of my plants. You can use some rust sulfur copper powder to stop the spores from multiplying but there is no way to reverse the damage. Best is to cut off the affected leaves and wait for regrowth.
Ringspot: This is caused by the ringspot virus which is due to the presence of aphids, also known as plant lice.
Burnt leaves: Too much direct sun can burn your Oxalis, especially if you have moved it from a medium light location to a high light location too quickly. You will know if your leaves are burnt if they look dry and crispy on the edges. This is different to Rust which looks more like mold all over the leaves.
Characteristics: Oxalis came to the United States in the 1980s and its popularity continues to grow. Indoors. When the weather is warm and there is adequate moisture, the Oxalis blooms with small, pale bell like flowers. There are about 300 species of Oxalis, the green leaf variety that makes great indoor plants is the Oxalis Regnellii. Oxalis gets its name from the fact that it’s high in Oxalic acid due to its tangy taste.
Dormancy: Oxalis occasionally go dormant and this happens suddenly in summer (which is quite strange for plants as it’s the growing season), this usually happens every 2-7 years, it may look like your Oxalis has died. Don’t panic! Simply stop watering and let the soil dry and put it in a dark corner. In about 2-4 weeks you will see a new leaf emerge and then you can start to water again and move it back into a sunny spot. They can also go dormant when temperatures exceed 80°F/27°C
Toxicity: Oxalis is classified as an edible plant, however it’s very bitter for humans. Oxalis is poisonous to pets if eaten. Watch out for kitties that chew on the leaves.
Examples of Oxalis in good lighting positions
Happy Growing.
So much info I didn’t know my late father had oxalis in the kitchen and I have a cutting from that plant to remember my Dad so it’s great to know more about caring for it
Yes, Oxalis are known to live for a long time and passed down from generations to generation and are referred to as ‘heirloom plants’. They are fun to grown because how often do you see purple leaves!
Thank you so much for adding in the rust spots! Any other site I’ve looked at has NOT mentioned that. I appreciate it!
Yea I had rust on my oxalis which is how I know about it. Cutting off the leaves wasn’t as bad as I thought, they grow back pretty quickly.
do you cut just the leaves or the stems too?
You can cut the stems all the way back to the bulb. If you cut the leaves the stems will die anyway and will fall off in a few days.
Thanks for the info on the rust. I’ve had my oxalis for a year now. They were beautiful and 4 months ago it just completely died. And had rusts on them. I wasn’t sure what to do so repotted it to see if there was any bulbs. We are just in the first 2 weeks of spring here and it’s starting to grow beautiful again but noticed that the leaves have the signs of rusts. If I cut all the stem off nad only the bulb will it grow again?
Yes it should grow back, the bulb should be rooted and as long is it has water and light it should regerminate. I would try and locate why is getting rust again, make sure its not to crowded with the other plants, the rust spores are usually from another infected plant. You could also use a rust powder to stop the spread. The anti rust powder(sulpher) will kill the current rust spores (although the current oxalis leave will be permanently damaged by the rust and only new leave will grow nicely)
Hi! I’m new to the oxalis world and found your article very helpful.
I’d like your help with a few questions.
My plant is very recent, only three stems with leaves (for now) and a flower stem. One of the stems, the newest one, has one leave smaller and under developed. The two other ones are already big and have their full colour. Is this normal/ commun?Have I done something wrong?
I’ve also seen a few flying bugs, similar to fruit flies, coming out of the soil. What can I do about this?
Thank you
Hi usually the new stems will grow pretty quickly to the size of the existing ones (ie within a few weeks). The fact that you have fungal gnats (what look like fruit flies) is a problem. They come because the top of your soil has been too damp for too long and the gnat larvae have bred. The best things to do is get those Yellow sticky fly papers to catch the existing gnats. Ensure you don’t keep your soil too damp, only water when top of the soil has been dry for 2 days. The gnats are generally harmless… Read more »
Well mine is ok but is it normal that I need to pick at the plant every couple of days, because some stems become limp and sort of wet, soggy, I just pull it out but just wondering if anyone else has had that happen to their oxalis?
This happens with mine as well, its usually due to inconsistent watering or letting the oxalis dry out. If the Oxalis is correctly watered the stems won’t die and shrivel up ever few days. Just keep it watered and you will get more stems and thicker growth.
Great, thanks. I think I will get this one the plantmaid
I’ve accidentally left mine out in the pouring rain and I think I’ve drowned it. Leaves are wilting, and I can’t repot or anything until I get the chance to after midterm season. What should I do to revive it?
Oxalis is a bulb so they don’t like sitting in water, it will eventually rot the bulb. To dry out the soil, leaving it on the window shelf in full sun is probably the easiest option. Oxalis would rather be dry then flooded with water. If you don’t think the soil will dry out within 4 days then I would repot it. I’m assuming your pot has a drainage hole at the bottom, so it should dry out fairly quickly if you keep it away from the rain and water.