Oxalis: wood sorrel
Height 5-10cm (2-4in)
Planting distance 15-30cm (6-12in)
Flowers in spring, summer or autumn
Sun or light shade
Bulbs available in early autumn
Many members of the wood sorrel genus are invasive weeds, but a few of these hardy, low-growing plants make graceful additions to a rock garden or as low edgings to borders. All have neat clumps of handsome foliage comprised of several leaflets; the funnel-shaped, with five petals, open wide in full sun.
Oxalis acetosella is the well-known native wood sorrel, not a true bulbous species but it spreads to 30cm (12in) from a creeping rhi-zome. It has neat tufts of pale green, shamrock-like leaves, and pearl-white flowers faintly veined with pink, in early to late spring. It grows only 5cm (2in) high and is suited to a shady and moist woodland setting where it will naturalize freely. The variety ‘Purpurescens’ is deep rose-pink. Oxalis adenophylla grows 7.5-10cm (3-4in) high from a bulbous rhizome and produces compact rosettes of crinkly grey foliage. The long-stemmed lilac-pink flowers are borne above the leaves from late spring to mid summer.
Oxalis enneaphylla is tuberous-rooted, hardy and only 7.5cm (3in) high. It has distinctive folded grey leaves and, in early and mid summer, large white, scented flowers. A pale rose-pink variety, ‘Rosea’, is sometimes available. Oxalis laciniata also has grey-green leaves, but with wavy margins. It grows to 10cm (4in) high, with thin stems rising from fleshy rhizomes. The solitary, fragrant flowers vary in colour from deep lavender-blue to pale purple, often with darker veins. They appear from late spring to late summer.
The plants die back after flowering. Oxalis lobata is near-hardy and needs protection from frost with a winter mulch. It grows 10cm (4in) high, bears bright green leaves and, in early autumn, yellow flowers.
Plant in early autumn, 5cm (2in) deep in well-drained soil containing plenty of organic material, and in full sun or light shade. Most types die back after flowering – mark their sites to avoid damaging the rootstocks during cultivation.
Lift, divide and replant bulbs and rhizomes in late summer, before the leaves die.
Pests and diseases