Procumbent yellow-sorrel

Oxalis corniculata

In other languages: Gehoornde klaverzuring (Nederlands) · Oxalis corniculé (Français)

Grows wild in Belgium.

Procumbent yellow-sorrel is a small, creeping plant with clover-like leaves and bright yellow flowers that has spread as a weed across almost the whole world; where it originally came from is uncertain. In Belgium it is naturalised: you mostly see it in the joints of patios and pavements, at the foot of walls, in flowerpots, greenhouses, nurseries and vegetable gardens, and rarely in real countryside. You can recognise it by its three-part leaves with heart-shaped leaflets, often purplish brown, by its stems that root at the nodes and by its yellow flowers with five petals. The upright, hairy seed capsules burst open when touched and shoot out their seeds. The leaves taste sour because of oxalic acid, just like sorrel.

Caution: Contains oxalic acid, like sorrel: a few leaves are harmless, but do not eat much of it and do not let children eat handfuls. Grazing animals, rabbits and other pets that eat a lot of it can become ill.

Updated on 9 October 2026

Light
Sun or partial shade
preferably some sun
Moisture
Dry to normal
no wet feet
Hardiness
down to -15 °C
protect young plants
Size
0.1 m
tall, 0.3 m wide
Flowering
May–October

Key facts
Height	0.1 m
Native to Belgium	No, naturalised
Flowering	May–October

Identify

How to recognise it

Growth form: Creeping, short-lived perennial or annual, 5–15 cm tall, with stems up to 30 cm long that root at the nodes.
Leaf: Three-part like clover, with inversely heart-shaped leaflets of 0.5–2 cm, green or purplish brown. At the base of the leaf stalk sit two small stipules, like little ears.
Flower: Bright yellow, about 1 cm across, with five petals, 1–5 together on one stalk. They only open in sunshine. Flowers from May to October.
Fruit/Seed: Upright, hairy, five-angled capsules of 1–2 cm on bent-back stalks. When ripe they burst at the slightest touch and shoot out the small brown seeds.
Roots: A taproot, plus roots at the nodes of the creeping stems.
Confusion with: Upright yellow-sorrel (Oxalis stricta) grows erect, does not root at the nodes and has no stipules on the leaf stalk. Clovers have no heart-shaped leaflets and carry their flowers in heads, like the small yellow heads of lesser trefoil and black medick.

Flowering: May–October

In your garden

Why grow it?

Flowers almost non-stop from May into October. Small bees and hoverflies visit the flowers, but to be honest its value for insects is limited.
One of the few plants that grow in the narrowest cracks and on hot stones: a green edge in a paved setting.
Fun to watch: the leaves fold up in the evening, the flowers only open in sunshine and the capsules shoot out their seed.
The purple-leaved form is decorative in a pot or between paving slabs, provided you keep it in check.
A few sour leaves are edible as a fresh garnish, like sorrel.

Procumbent yellow-sorrel: where does it grow best?

Grows mainly in places made by people: joints of patios and pavements, the foot of walls, greenhouses, flowerpots, nurseries and vegetable gardens.
Sun to partial shade; it likes warmth and tolerates the heat of paving.
Any free-draining soil, from sand to loam, dry to moderately moist.
If you want to keep it, grow it in a pot or between paving, not in borders or the vegetable patch, where it soon seeds about.

Goes well with

Biting stonecrop: Another plant for sunny cracks and low walls, with yellow stars in June.
Wild thyme: Fragrant pink flowers for bees between paving and on a dry edge.
Daisy: A classic of lawns and paving, flowering almost all year.
Common stork’s-bill: Small pink flowers on dry, open ground, with long-beaked fruits.

Maintenance

Procumbent yellow-sorrel: when and how to plant it?

Preferably do not plant it on purpose: it usually turns up by itself, as a stowaway in compost or in the pot of a new plant.
If you want the purple-leaved form as ground cover in a pot or between paving, plant a small rooted tuft in poor, free-draining soil in April–May.
Sun or partial shade; 20–30 cm apart is more than enough, as it fills the space itself.
Water only until it is established.
When buying pot plants, check the soil and pull out the seedlings if you do not want it in your borders.
Never plant it in or near a nature area, and do not dump garden waste with ripe seed in the countryside.

Care

Water: Not needed; in a pot only during prolonged drought.
Feeding: Not needed: it grows in the poorest spots.
Weeding: In the vegetable patch and borders, pull or hoe it out with its root before the capsules ripen. Loose bits of stem can root again.
Paving joints: Scrape out joints with a weeding knife or wire brush and refill them with sharp sand. Boiling water, for instance from the potatoes, kills young plants in the cracks.
Spreading: A mulch of wood chips or compost on borders slows germination; in pots a layer of gravel helps.

Tip: Weed it before the capsules ripen, and ideally after a shower: the taproot then comes out easily and you prevent hundreds of new plants.

Pruning and mowing

When: No pruning is needed. The best time to weed is from May to September, before the capsules burst.

How:

Pull plants out gently with their root, preferably after a shower when the soil is loose.
On plants you want to keep, cut off the flowering stems to limit self-seeding.
Put plants with capsules in the green waste bin or on a hot compost heap, not where the seed can drop.

Caution: If you pull up plants with ripe capsules you scatter the seed all around: weed before the seed sets, or hold a bag around the plant.

Pruning calendar and basic rules

Propagation

Seed: This is mainly how it spreads: the capsules shoot the seeds a metre or more. The seed stays viable for a few years and travels in compost and plant pots.
Creeping stems: The stems root at the nodes; broken pieces take root again. This is also how you can move the purple form on purpose.

Procumbent yellow-sorrel: how does it get through the winter?

Hardy to −15 °C: protect young plants.

In mild winters it stays green in sheltered cracks and in greenhouses; in hard frost the top growth dies back.
The seed overwinters in the soil and germinates in large numbers in spring.
In a heated greenhouse or conservatory it sometimes flowers almost all year round.

Diseases and pests

Stowaway in pots: It travels with pot plants from nurseries and garden centres. Remove seedlings from new pots and replace the top layer of compost if needed.
Self-seeding in the vegetable patch: Seeds itself in huge numbers. Weed early, hoe in dry weather and mulch the beds.
Paving joints: Hard to pull out of narrow cracks. Scraping, brushing and refilling the joints with sand works best.
Coming back after weeding: Bits of stem and seed in the soil produce new plants. Keep weeding consistently before seed set for a few seasons.

Through the year

March: First seedlings in paving joints and pots. Weed early.
April: Check new pot plants for stowaways.
May: Flowering begins. Weed before the capsules ripen.
June: Flowering and first ripe capsules. Scrape out paving joints.
July: Full flower. Mulch borders and vegetable beds.
August: Flowering and seed dispersal. Keep weeding.
September: Last big weeding session.
October: Flowering tails off. Refill paving joints with sand.

You and this species

Did you know?

Corniculata means ‘with little horns’, after the upright seed capsules.
The genus Oxalis takes its name from the Greek oxys, ‘sour’; the word oxalic acid comes from it too.
In the evening the leaflets fold down like an umbrella: a sleep movement shared by many wood-sorrels.

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