Wood-sorrels

Common Wood-sorrel Common Pink-sorrel Least Yellow-sorrel Least Yellow-sorrel

What are they?

The wood-sorrels are low-growing, herbaceous perennial plants with five-petalled, pink, yellow or white flowers and leaves typically comprising of three leaflets like those of clovers. We have just one native species which is often considered to be an indicator species for ancient woodland on acid soils. The flowers are usually carried in small clusters and are followed by elongate seed pods that are usually carried pointing vertically upward.

Where are they found?

Our one native species, Common Wood-sorrel, is found in shady places on acid soil. All other species are garden ornamentals that spread readily by seed, by vegetative parts such as small bulbils or by rooting readily at the nodes and forming spreading carpets. Species that form carpets are often found as urban weeds, growing from cracks in pavements or walls, or on gravel paths. The larger, pink-flowered species are often found where garden waste is dumped on roadsides, rough ground and grassy places.

Identification

Flower colour will be a first step to narrowing down the identification of a plant. Leaf detail can be important in the pink species, while flower detail is important in the yellow species.



Procumbent Yellow-sorrel      Oxalis corniculata

Introduced from the Mediterranean region. An abundant species in urban areas and often considered an invasive weeds in gardens (especially driveways and patios) and garden centre stock. Flowers June to September. A creeping plant that can cover extensive areas of ground. Leaves may be green but more often the entire plant (except the flowers) is flushed deep reddish-purple. Green-leaved plants can be difficult to tell from Least Yellow-sorrel but flowers have all 10 stamens with anthers and the flowers are typically in clusters of two to eight (though the flowers not all opening at once).

Procumbent Yellow-sorrel Procumbent Yellow-sorrel Procumbent Yellow-sorrel Procumbent Yellow-sorrel
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Least Yellow-sorrel      Oxalis exilis

Introduced from Australia and New Zealand. Much less common than Procumbent Yellow-sorrel but still widespread and perhaps increasing. A weed of garden borders, lawns and drives. Flowers June to September. A creeping plant that can cover extensive areas of ground. Leaves bright green. Can be difficult to tell from Procumbent Yellow-sorrel but flowers have only 5 of the 10 stamens with anthers and the flowers are typically solitary.

Least Yellow-sorrel Least Yellow-sorrel Least Yellow-sorrel Least Yellow-sorrel
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Upright Yellow-sorrel      Oxalis stricta

Introduced from North America. Rare as an urban weed. Flowers July to October. An upright plant which is often confused with Procumbent Yellow-sorrel, but usually easily identified by the covering of patent white hairs on the stems and the upright (not reflexed) stalks to the seed pods.

Upright Yellow-sorrel Upright Yellow-sorrel Upright Yellow-sorrel Upright Yellow-sorrel
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Common Wood-sorrel      Oxalis acetosella

Native. Found in shady places on acid soils in woodland and occasionally hedgebanks and cemeteries. Flowers April to May. The white flowers with pale lilac veins and the fresh green leaves in creeping mounds are distinctive.

Common Wood-sorrel Common Wood-sorrel Common Wood-sorrel Common Wood-sorrel
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Common Pink-sorrel      Oxalis articulata

Introduced from southern South America. Common and widespread as a garden escape on grassy banks, roadsides and rough ground. Flowers May to October. A tussock-like plant with low mounds of green leaves, the leaflets bearing small, orange spots on the underside towards the tip. Flowers bright carmine pink with a darker centre, rarely all white.

Common Pink-sorrel Common Pink-sorrel Common Pink-sorrel Common Pink-sorrel
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Leaf underside


Broad-leaved Pink-sorrel      Oxalis latifolia

Introduced from northern South America. Rare as a garden escape. Flowers May to September. A more spreading plant than Common Pink-sorrel forming looser and more extensive patches of leaves. Leaflets without orange spots on the back. Flowers pink to pale lilac in colour, usually with a whitish centre; occasionally all white. Leaves rather angular in appearance with the three leaflets typically bent downward from their bases.

Broad-leaved Pink-sorrel Broad-leaved Pink-sorrel Broad-leaved Pink-sorrel Broad-leaved Pink-sorrel
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Pale Pink-sorrel      Oxalis incarnata

Introduced from South Africa. Frequent as a garden escape and seeming to favour dry, gravelly places or the foot of walls. Flowers May to July. An upright plant to around 30cm in height (though often less), that forms spreading patches of yellow-green leaves. Flowers delicate, very pale pink, almost white.

Pale Pink-sorrel Pale Pink-sorrel Pale Pink-sorrel Pale Pink-sorrel
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