The Oxalis triangularis is also called the purple shamrock or the false shamrock, because of the shape and color of its leaves. This plant can be grown as either an indoor or outdoor plant. One of the reasons for its popularity is that it is photophilic, meaning that its leaves and flowers close at night and open up again in the morning, prompted by the light.
In this article, we will discuss the proper cultural care of Oxalis triangularis and how to correctly propagate it. So, if you are thinking about adding this plant to your collection, just keep reading.
Oxalis triangularis dormancy
Before we dive into the proper care of Oxalis triangularis, it is important to first discuss its dormancy period. Being aware of this crucial part of the plant’s life will give us a better understanding of why such proper care is important.
When the Oxalis triangularis is dormant, it is not actively growing and is also at its most vulnerable.
The plant’s dormancy starts immediately after its growing season, and you will know it is starting because the leaves will begin to droop and will no longer open up, even during the day. You may even think the plant is dying. Just allow the foliage to die back and remove any dead leaves.
It is completely fine, and even advisable, to transfer the plant to a dimmer, darker spot for a couple of weeks. Refrain from fertilizing or watering the plant while it is dormant.
Eventually, you will see new growth and you can then resume the usual Oxalis triangularis care routine. Try not to water it as much in the beginning, though, and rather increase the amount of water gradually as the plant gets bigger.
The rest of our discussion on Oxalis triangularis care will focus on how to care for the plant in its growing period.
Oxalis triangularis care
1. Water requirements
The best rule to follow when it comes to watering your Oxalis triangularis is to touch the top inch of soil before you water it. If the soil is dry to the touch, water the plant, but if the soil is still a bit damp, wait a few days and check it again.
As mentioned above, refrain from watering the plant when it is dormant because this might lead to overwatering and even root rot. Root rot is when the roots of the plant drown and die in waterlogged soil. The dead roots will start to rot and become susceptible to opportunistic pathogens. Once the roots are infected, the rot will become more aggressive and spread upward to the rest of the plant. This can ultimately lead to the plant’s death.
Underwatering should also be avoided, because if the plant is left to dry out for too long, it can go dormant before it should, which is something you would rather avoid.
2. Light requirements
Give your Oxalis triangularis medium to bright, indirect light. The source of light can be the sun or it can be artificial, especially in cases when sunlight is scarce, such as during the winter.
Do not leave the plant in a spot where it gets bright, direct, unfiltered light, as this can lead to sun damage and leaf scorch. If the sunlight entering your window is too harsh and bright, diffuse the light by placing a sheer curtain over the window.
When you are using grow lights, start by keeping the plant far from the lights and gradually move the lights closer until you find the ideal distance.
3. Temperature and humidity requirements
The humidity inside most households is typically fine for Oxalis triangularis. This plant is not too finicky about humidity, so as long as the humidity levels are not in the extremes, it should be alright.
The same goes for regular room temperature. As long as the temperature range in the room is between 60 and 75 degrees Fahrenheit, the plant should be fine. But, as we mentioned above, drying out the plant can cause it to go dormant and increased temperatures can dry it out faster. Keep the temperature from ever reaching above 80 degrees Fahrenheit to avoid stressing the plant into premature dormancy.
4. Soil requirements
Typically, normal indoor plant potting soil will do fine for the Oxalis triangularis, but you can make the soil mix even more porous and airy by adding in perlite to it. The soil mix should be able to hold enough moisture not to dry out too quickly, but it should also be able to drain well enough to get rid of any excess water. Adding coco peat will help with moisture retention.
If the soil is dense and compact, you may need to replace it with a looser soil mix to keep the plant happy.
5. Fertilizer requirements
Do not feed the plant when it is dormant; only do so when it is actively growing. Give the plant half-strength, liquid houseplant fertilizer twice a month to help it grow healthily. Do not overfeed the plant, because this can lead to toxicity in the soil and will end up doing more harm than good.
Oxalis triangularis propagation
Propagation by division
You can divide a full plant into as many as four or more sections, with each section getting its own bulb.
Take the plant from its pot very gently and remove a section. Make sure you have taken out the whole root before doing this, so that you inflict as little damage as possible. If you are lucky, the roots will not be tangled when you remove them from the soil, but if they are, you can use sterilized scissors to cut the tangled ones. Just try to keep as many intact roots as possible when separating the sections.
Plant these different sections in their own individual pots, using well-draining soil mix. Water the soil well, but not too much. Place the new plants in a spot where they can get bright, indirect light as they grow. Do not be worried if the plants look limp after repotting; this is just transplant shock and the plant will recover as it adapts to its new situation.
Propagation by bulbs
You can also propagate your plant by placing each bulb into its own pot. This method is done while the plant is dormant and has died back.
Once you have taken the bulbs from the old potting soil, plant each bulb one or two inches below the soil in its own pot using moistened, well-draining soil mix. If you are planting multiple bulbs in one pot, make sure you space them out well enough that each has sufficient space to grow.
Place the pot where the plants can get bright, indirect light as they grow.
Ideally, this is done at the tail-end of dormancy. After a few weeks, you will notice new growth appearing where you planted the bulbs.
Oxalis triangularis are quirky, photophilic little plants with beautifully purple leaves. They may look delicate and fragile, but if you know how to handle them properly, you will have no problem caring for them and propagating them.
These plants appreciate medium to bright, indirect light, only need water when the top inch of their soil is dry, only need fertilizing twice a month when actively growing, and do well in normal room temperature and normal humidity.
This plant can be propagated either by dividing it into sections, or by replanting the bulbs individually when the plant is dormant.
Image: istockphoto.com / Nahhan