How to Grow and Care for Purple Shamrock (False Shamrock)

Purple shamrock, also known as false shamrock, is a unique plant with deep purple, nearly black foliage that looks like fluttering butterflies. Its triangular leaves grow in threes and fold up like an umbrella at night or on cloudy days, opening again in the morning. This plant also blooms with tiny white, pale pink, or lavender flowers.
Purple shamrock thrives in spots with at least four hours of sunlight, well-draining soil, and moderate temperature and humidity. It’s important to note that all parts of the plant are toxic to people and pets.

Purple Shamrock Care

Here are the main care requirements for growing a purple shamrock.

• Provide the plant with a sunny spot and water it whenever the soil starts to dry out.
• Make sure the soil is well-draining.
• Feed your shamrock throughout its growing season to encourage healthy growth.
• Rotate a purple shamrock houseplant so it doesn’t grow leggy.
• Reduce watering and stop feeding a dormant purple shamrock (the foliage degrades at this stage). When new foliage begins to grow, resume normal care.

Light

Purple shamrock grows best in full sun to partial shade, needing around four hours of direct sunlight per day. Outdoors, provide protection from the hot afternoon sun (in hot climates); indoors, grow near a window with bright light, like a south-facing one.

Soil

The purple shamrock can grow in a variety of soil types with good drainage, but prefers loamy or sandy soil. For container growth, a general, well-draining potting mix should be fine.

Roots are prone to rotting if the soil retains too much moisture.

Water

During the growing season, water whenever the top inch of soil has dried out. When the plant is dormant in the summer, lightly water about every two to three weeks to prevent the soil from drying out completely.

Temperature and Humidity

Purple shamrock prefers temperatures between 60 and 75°F, and can tolerate nighttime temperatures down to 50°F. Protect the plants from strong winds outdoors and drafts indoors, especially from air conditioners and heaters as they can damage the foliage.

A moderate humidity level is ideal for purple shamrock plants.

Fertilizer

Use either a slow-release or liquid fertilizer on the purple shamrock plant during its growing season, following label instructions. Indoors, a liquid fertilizer for houseplants is ideal. Mixing some compost into the soil also can help to promote healthy growth.

Types of Shamrock

Besides the purple shamrock, there are several plants in the oxalis genus that use the common name of shamrock, including:

• Oxalis acetosella: Also known as the wood sorrel or shamrock, this plant has bright green, heart-shaped leaves that occur in groups of three.
• Oxalis tetraphylla: This plant is commonly known as four-leaved sorrel or lucky clover because of its four split leaves. The leaves are bright green with a maroon center.
• Oxalis lasiandra: This species is referred to as the Mexican shamrock or palm tree oxalis. It grows a little over a foot tall and bears bright pink flowers to crimson flowers.
• Oxalis adenophylla: This species is commonly known as the Chilean oxalis or silver shamrock. It features silvery green leaves and bears pink flowers with deep purple centers.
• Oxalis bowiei: The common names for this species include the Cape shamrock, Bowie’s wood sorrel, and red flower wood sorrel. It bears rose-colored to reddish-purple blooms.

Propagating Purple Shamrock

Mature purple shamrocks can be propagated by division or bulbs (these plants grow from bulbs, rather than seeds) during their growing season.

By Division

Division is a cost-effective way to get new plants, and it prevents the mature plant from becoming overcrowded. Here’s how to propagate by division:

1. Carefully dig up the plant, keeping the roots as intact as possible.
2. Gently pull apart the root ball to divide it in half (or into more sections if your plant is very large). Avoid tearing the roots, though you can use sterile garden scissors on very tangled roots.
3. Replant each new section either in the ground or in a container that’s just slightly larger than its root ball. Water the plants.

By Bulbs

The best time to plant bulbs is in the spring. Here’s how to propagate by bulbs:

1. Plant the bulbs with the narrower end facing up roughly 1 to 2 inches down in the soil.
2. Space multiple bulbs approximately 3 to 4 inches apart.
3. Water the soil after planting, and make sure it does not remain waterlogged. Continue to water whenever the top 1 to 2 inches of soil dries out.
4. Make sure the bulbs are in a warm, bright spot (either in a container or in the ground). You should see growth in three to four weeks.

Potting and Repotting Purple Shamrock

Select a pot that’s just slightly larger than your purple shamrock’s root ball. Make sure it has ample drainage holes. An unglazed clay container is ideal because it will allow excess soil moisture to escape through its walls. Use a quality all-purpose potting mix that drains well.

Plan to repot every two years in just one container size up. Gently loosen the plant from its old container, and shake off loose soil. Then, replant it at the same depth in its new container with fresh potting mix. Finally, water the plant.

Overwintering

When grown outside of their hardiness zones, purple shamrocks must be kept indoors for the winter. Bring them inside well before any frost is in the forecast and while the nights are still above 50°F.

Place the plant by your brightest window, ideally one that faces south, and make sure it’s not in the line of any drafts. Continue to water as you did when the plant was outdoors.

Common Pests & Plant Diseases

Purple shamrocks are prone to a few common pests and diseases. Some pests include mealybugs, aphids, and spider mites. Treat infestations with an insecticidal soap.

A common disease of purple shamrocks is powdery mildew, a fungal disease that creates white spots on the foliage. This often is a result of humid conditions and poor airflow. Avoid overhead watering, and don’t crowd your plants.

How to Get Purple Shamrock to Bloom

Bloom Months

Purple shamrock plants actively grow and flower during the fall to spring and go dormant in the summer.

What Do Purple Shamrock Flowers Look and Smell Like?

Purple shamrock flowers are small, five-petal white, pink, or lavender blooms that grow in clusters above the foliage. Just like the leaves, the sweet-scented blooms close at night and on cloudy days.

How to Encourage More Blooms

Encourage blooms with enough sunlight, moisture, and fertilizer. Plants that are struggling with deficiencies will likely not bloom profusely or even at all. But a healthy shamrock grown in the conditions it likes will readily rebloom year after year.

Common Problems With Purple Shamrock

Purple shamrock plants are generally easy to maintain if you give them the proper growing conditions. But some common problems arise due to environmental issues.

Drooping Leaves

Drooping leaves are often due to insufficient water or light (or both). However, this also might be a sign of the plant’s natural dormancy period if the temperature is rising. If your plant is not going into its dormant stage, try giving it a little more light to see whether that perks up the foliage. Also, make sure you’re not letting the soil dry out.

Leaves Turning Brown

If the leaves are turning brown or they don’t look as vibrant as usual, it can be a sign that the plant is heading into dormancy. Allow it to go through this natural process, cut back on watering and feeding, and resume when new growth appears. At that point, trim off any degraded foliage.