11 Tips For Growing Beautiful Oxalis Flowers in Pots or Containers

Oxalis, also known as wood sorrel, is a lovely genus of plants that grows naturally on every continent except Antarctica. These pretty little plants are commonly known as “false shamrocks” because of their similar leaf formation, but they are unrelated. As houseplants, oxalis containers are sure to be catch your attention with their bright, bouncy foliage.

Commonly kept as houseplants, oxalis usually has leaves of deep purple, bright green, or a combination of the two, as seen in the ‘Iron Cross’ variety. They are flowering plants, typically with yellow, purple, pink, or white flowers. 

Oxalis tends to spread and be difficult to control when planted in the ground, making it an ideal container plant. It will fill a pot quickly and bring a lot of color and movement to a space. Here are 11 tips for growing stunning oxalis plants in containers.

Use the Right Soil

Oxalis is tolerant of a wide range of soil types, and while it will survive in clay soil, it will thrive in loose rather than compacted soil. This is a plant that likes to form deep roots. Loose soil will encourage your plant to send out those deep roots, which yields a larger, healthier plant.

Most commercially available potting mixes are slightly acidic, which is suitable for oxalis. However, these plants are tolerant regarding pH, so acidity is not a must. Soil that drains well but holds some moisture is going to be the ideal type. Speaking of drainage, that brings us to the issue of containers.

Deep Container

Since oxalis plants like to stay consistently moist, root rot can be an issue if the pot doesn’t have adequate drainage. A terracotta pot will help wick some water from the roots, but any pot with a decent drainage hole will suffice.

As I mentioned, wood sorrel likes to send out deep roots. This characteristic can be problematic if you are trying to control the spread of oxalis in the garden, but for container plants, it is actually a good thing. Deep roots lend a plant greater adaptability, plus increased nutrient and water uptake.

In addition to depth, the size of the pot is a factor to consider. Oxalis likes to be slightly rootbound. Choose a pot that is just slightly larger than the root ball of your oxalis plant. 

Provide Partial Shade

Oxalis is tolerant of different lighting conditions. This is a very flexible plant in many ways. Typically, they are listed as part-shade to full-shade plants, but in my experience, they enjoy a good dose of the morning sun. The spot where my oxalis grows happiest gets direct sun for about 3 hours in the morning. By noon, it spends the remainder of the day in the shade.

The afternoon sun is more intense and causes water to evaporate faster. Since wood sorrel likes moisture, direct sun in the afternoon is likely to cause wilting.

Of course, this depends on the climate. Oxalis will do fine with a lot of sun during cooler weather, but in the heat of the summer, particularly in overall warmer climates, this plant will prefer shade for much of the hottest part of the day.

Water Correctly

Woodland streams are the most common place to find oxalis growing wild. In other words, it likes moisture and prefers consistently moist soil. It also needs proper good drainage to ward off root rot. As long as your container drains properly, watering should be an easy part of caring for this plant.

If you keep your oxalis indoors, aim to water once every 1-2 weeks. I keep mine outside because it seems happiest there, and I water it every 2-3 days. I increase the watering frequency to every 1-2 days in the hottest summer months. 

Oxalis plants occasionally go dormant, and in this period, they might appear to be dying. However, this is normal, and the best practice is to water very sparingly, if at all, during this time. The plant doesn’t take in much water when dormant, so root rot is a more significant concern during dormancy.

Keep it Warm

Oxalis plants prefer temperate climates. When the temperature rises above 80°F, it will need relief from the sun, and below 50°F, it will likely head into dormancy. This makes it a great houseplant, as 65°-75°F is an ideal range for Oxalis. 

Naturally, this has implications if you are growing wood sorrel outdoors. In cooler climates, getting a bit of direct sun should be fine. However, in warmer climates, this plant will need respite from the direct sun when the temperature rises into the 80°s and above.

Rotate the Container

Oxalis tends to follow the sun, especially when kept indoors or in a mostly shaded space. You will notice that the leaves and flowers of this plant will lean and turn their faces in the direction of the light. 

Rotating your pot every two weeks will lend itself to a fuller, more well-balanced plant. A nice, balanced oxalis plant is a beautiful thing. These plants have a lot of movement; when a breeze blows, the stems will dance with the wind. A regular rotation schedule will keep those stems and leaves nice and uniform.

Lightly Fertilize

Fertility is another area where wood sorrel is flexible and easygoing. Oxalis does not technically need fertilizer. It efficiently utilizes the nutrients in the soil and grows quickly even without fertilizing. That said, using fertilizer will increase the plant’s growing period and promote blooms. 

Oxalis plants produce pretty little flowers in yellow, pink, purple, and white, depending on the variety. The flowers are not usually the focal point for this plant, but they are lovely and add a nice little pop of color. Fertilizing once a month during spring and summer will boost your plant’s blooming duration and quality. Any balanced houseplant fertilizer will work.

Prune 

Speaking of flowers, deadheading and pruning is a quick and easy task that will lead to a longer and more prolific blooming and growing season. Pruning oxalis is more about deadheading than anything else. 

You can use garden shears, or use your fingers, to pinch off spent flower stems. Also, remove any leaves that have run their course. Anything that doesn’t stand upright on this plant should be removed to make way for new growth. Removing the dead weight will help the plant to redirect water and nutrients to new growth.

Look Out for These Pests

Interestingly, wood sorrel does not have many pests that prefer it as a food source. It contains oxalic acid, which is an irritant and even toxic to some pests. In fact, oxalic acid is one of the most common treatments used by beekeepers to control the population of varroa mites in a bee colony. 

There are a few typical garden pests that don’t discriminate, though. Among them are aphids, which nearly every gardener has had to deal with at some point.

These little guys feed on the sap of plants and leave behind a sticky residue that can cause mold to grow. Neem oil is very effective in getting rid of aphids, and so is insecticidal soap. 

Spider mites and whiteflies also snack on oxalis plants, leaving stems and foliage shriveled and unhealthy. Both of these pests can be eradicated using neem oil or insecticidal soaps. Always treat outdoor plants in the evening to avoid spraying while beneficial insects are active. Try not to treat when the plant is in bloom, as this could harm pollinators.

Propagate

Propagating oxalis is very simple. You can propagate your plant by division or grow it from seed. If you already have a healthy plant, division is the fastest route to more healthy, mature plants. Growing from seed is typically successful but much more time-consuming. As your plant gets larger, you may want to divide it just for the sake of creating space in the pot for new growth. 

To divide a wood sorrel plant:

1. Gently remove it from its container.
2. Loosen the soil from the root system.
3. Notice the corms or tubers of the oxalis plant.
4. Gently separate these tubers, making sure each one has rhizomes attached.
5. Plant each tuber in its own container. 
6. Water thoroughly.

Don’t be alarmed if your newly planted oxalis babies look a bit wilted and droopy for a while. As soon as they develop their own root systems, they should perk up and look lively again.

Repot Regularly

Repotting and propagation go hand in hand. When repotting, it is the prime time to remove a few corms and start new plants. After removing your plant from the pot and making any divisions, inspect the roots for health and any possible root rot. Use clean shears to remove any root tissue that looks rotten or dead. 

If you are dividing, you can replant your parent plant in its original container with fresh, new potting soil. Over time, soil compacts, and this inhibits root growth.

Repotting with fresh, loose soil encourages new root development. Fill your pot so that the plant is covered up to its original soil line, and feel free to top it off with some mulch for good keeping.