Some species are considered aggressive garden weeds, while others are prized ornamentals.

Does it need full sun?

Most prefer bright, indirect light to partial shade.

Plant guide

Shamrock.

Oxalis

Pronounced ok-SAL-iss try-ang-gu-LAR-iss

Also known as Sorrel, Sorrels, Suurings, Wood Sorrel, Wood-sorrels, Woodsorrel, Woodsorrels, billy goat grass

Largeflower pink-sorrel — Photo by WATANABE Hitoshi 渡辺仁 (CC BY) via iNaturalist

The purple shamrock is a charming plant known for its deep, triangular leaves that fold up at night. It is a bulbous perennial that adds a lovely splash of color to any indoor space. You will find it quite responsive to light, moving its foliage throughout the day.

At a glance

Care level: Easy
Plant type: Bulbous perennial
Light: Bright indirect light is best for keeping the leaves vibrant.
Indoor light: bright-indirect
Water: Every 7 to 10 days
Mature size: 30 cm tall and 30 cm wide
Growth rate: medium
Hardiness: USDA 7 to 10
Bloom time: Spring to summer

Care

Keep the soil lightly moist and provide plenty of bright, indirect light to maintain its vibrant color. Watch for leggy stems, which indicate the plant needs more light, and allow it a short dormant period if it begins to look tired. Ensure the pot has good drainage to prevent the bulbs from sitting in water.

Watering: Water when the top inch of soil feels dry to the touch.
Feeding: Use a balanced liquid fertilizer diluted to half strength during the growing season.
Pruning: Trim back any yellowing or damaged stems at the base to encourage fresh growth.
Repotting: Repot in the spring if the bulbs become too crowded in the container.
Soil: Well draining peat based potting mix
Soil pH: 6.0 to 7.0
Temperature: 15 to 24°C
Humidity: 40 to 60%
Drought tolerance: moderate
Lifespan: Perennial, typically 3 to 5 years.
Deer and rabbits: moderate

Signs it needs repotting

Roots growing out of the drainage holes.
The plant stops producing new leaves.
Water runs straight through the pot without soaking in.

Safety

People: The plant is considered toxic if consumed in large amounts due to high levels of oxalic acid.
Pets: This plant is toxic to cats and dogs if ingested due to soluble calcium oxalates.
Children: Keep this plant away from small children as ingestion of large quantities of leaves can cause stomach upset.
Contact allergens: Some individuals may experience mild skin irritation from handling the sap.
Airborne allergens: There is no significant evidence of respiratory allergies from this plant.
Edibility: Oxalis contains oxalic acid, which can be harmful in large quantities or for people with kidney issues.

How to identify it

Deep purple triangular leaflets
Leaves fold closed at night
Delicate white or pink flowers
Grows from small scaly bulbs

Height: 0.15 to 0.3m
Spread: 0.15 to 0.3m
Leaves: purple, burgundy, evergreen
Flowers: white, pink, 1 to 2cm

Common problems

Rust — Small orange or brown spots appear on the undersides of leaves.
Aphids — Tiny insects that suck sap from new growth and cause leaf curling.

Growing it

Propagation: division
When to plant: spring
Overwintering: If growing outdoors in cold climates, bring containers inside or mulch heavily. If the plant goes dormant, keep the soil barely moist until new growth appears.
In containers: Oxalis grows very well in pots, and a 6 inch container is usually sufficient for a single plant.

Division of Bulbs

Gently lift the plant from its pot during the dormant season.
Separate the small bulbs or offsets from the main clump.
Replant the offsets in fresh, well draining potting mix.

Pair Oxalis with plants that have similar water needs to ensure they thrive together without one outcompeting the other.

Grows well with

Ferns — They share similar light and moisture requirements in shady garden spots.
Hostas — Their broad leaves provide a nice textural contrast to the delicate Oxalis foliage.

Keep away from

Turf Grass — Oxalis can become invasive and compete aggressively with lawn grasses.

Similar species

Shamrock — Often confused due to the three leaf structure, though they are unrelated.

Science

Family: Oxalidaceae
Genus: Oxalis
Order: Oxalidales
Class: Magnoliopsida
Native range: Found globally, with high diversity in South America and South Africa.
Conservation: Most common Oxalis species are widespread and not of conservation concern.

It often colonizes disturbed soil or forest floors, utilizing its ability to grow from small bulbs or rhizomes to spread quickly.

Value to wildlife: nectar source
Pollinators: bees, butterflies
Uses: ornamental groundcover, container plant, rock garden accent

Through the year

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Flowering

Fruiting

Foliage

Ecological indicators

Salinity: 2/9
Soil reaction: 5/9
Light: 5/9
Temperature: 5/9
Moisture: 4/9
Nutrients: 4/9

Taxonomy resolved against GBIF.

Questions people ask

Is Oxalis a weed?: Some species are considered aggressive garden weeds, while others are prized ornamentals.
Does it need full sun?: Most prefer bright, indirect light to partial shade.

Where the name comes from

The name Oxalis is derived from the Greek word oxys, meaning acid, referring to the sour taste of the leaves. The common name wood sorrel also highlights this acidic flavor profile.

Good to know

The name Oxalis comes from the Greek word for acid.
Some species are known as wood sorrel.
The leaves are often shaped like clover but are not true clovers.

Is your shamrock looking unwell?

This page is a general guide. Pocket Botanist diagnoses problems from a photo of your actual plant, works out watering for your light and conditions, and reminds you when care is due.

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This guide was generated with AI and checked against GBIF taxonomy. It is general information, not horticultural or veterinary advice. Read about how we build these guides.