Wild Plum

Prunus domestica subsp. insititia

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At a Glance

The wild plum, Prunus domestica subsp. insititia, is a deciduous shrub or small tree native to much of Europe and western Asia, long naturalised in the British Isles. It is the botanical umbrella for the familiar orchard fruits known as damsons, bullaces and the closely related mirabelles, and it sits at the heart of several centuries of British culinary tradition. Reliable, hardy and undemanding once established, it remains one of the best fruit trees for smaller gardens and exposed sites.

Overview

Wild plum belongs to the rose family (Rosaceae) and is a hexaploid subspecies of the European plum. Although the true sloe (Prunus spinosa) is a separate species, the two are frequently confused: sloes are generally smaller, more austere in flavour, and borne on a spiny shrub. P. d. subsp. insititia tends to make a larger, less thorny plant with bigger, sweeter fruit, although hybrids do occur where their ranges overlap.

In the UK the subspecies is represented principally by damsons — the small, oval, deep purple plums long associated with the Lyth and Teme valleys of Shropshire and Worcestershire — and by bullaces, a rounder, more austere form often found in old hedgerows. Yellow-green fruited forms, sometimes called White Bullaces, also occur. The plant is well suited to British conditions, flowering after the worst of the spring frosts in most years and ripening in early autumn.

Appearance

Wild plum typically grows as a rounded, dense-headed shrub or small tree reaching 2–6 m. Its bark is dark grey-brown, smooth on young wood and becoming finely cracked with age. The branches often carry short spur-like side shoots, and on ungrafted stock a tendency to throw root suckers can produce thickets over time.

Leaves are alternate, ovate to elliptical, 4–8 cm long with a finely serrated margin. They are a darker, slightly glossy green above and paler beneath, often with a faint down along the veins. Autumn colour is generally modest, ranging from pale yellow to a russet-brown.

Flowers appear in April or May, usually before or with the new leaves. They are white, five-petalled and around 2–3 cm across, borne singly or in pairs along the previous year's wood. The fruit is a drupe, round to slightly oval, 2–4 cm in diameter. Skin colour depends on form: the classic damson is a deep purple-black with a waxy bloom; bullaces may be similar or paler; mirabelle-type forms are a translucent yellow-green. The stone tends to cling to the flesh rather than parting freely.

Growing Conditions

Wild plum is hardy throughout the UK (RHS H5) and tolerates winter cold down to around –15 °C, which is sufficient to break dormancy reliably. It performs best on a deep, well-drained fertile loam but is unusually tolerant of heavier clay and of lime-rich, slightly alkaline soils — a useful trait on chalk districts where many other stone fruit struggle. Soil pH between about 6.5 and 8.0 is ideal; very shallow chalk or permanently waterlogged ground should be avoided.

A position in full sun gives the heaviest crops. Light, dappled shade is tolerated but yields are reduced and the fruit may not ripen evenly in cool summers. Shelter from cold spring winds helps protect blossom, although flowering is late enough that most UK sites escape serious frost damage.

Most forms are self-fertile, so a single tree will usually crop well on its own. Planting two compatible cultivars can improve fruit set in a poor spring and extend the harvest window. Bees are the main pollinators.

Planting and Care

Bare-root stock is best planted between November and March while dormant, in a hole wide enough to take the roots without bending. Container-grown plants can go in at any time of year provided they are kept watered through the first summer. Space trees 3–5 m apart depending on rootstock and desired final size.

Garden trees are usually grafted onto a semi-dwarfing rootstock such as 'St Julien A', which keeps the tree to a manageable 3–4 m, or onto the more vigorous 'Brompton' for larger specimens. Own-root plants raised from suckers or hardwood cuttings remain common in older plantings and sucker freely.

Watering is important during the first two growing seasons and during prolonged dry spells while the fruit is swelling in midsummer. A light top-dressing of a balanced general fertiliser such as Growmore in late winter, followed by a 5–8 cm mulch of well-rotted garden compost or manure kept clear of the trunk, is sufficient on most soils. On thin, sandy soils an additional potassium-rich feed in early summer can improve fruit size and flavour.

Pruning should be kept light on established trees. The four Ds — dead, damaged, diseased and crossing wood — can be removed in summer, which is also the safest time to limit the risk of silver leaf disease. Any larger wounds can be sealed with a proprietary pruning paint. Suckers arising from below the graft should be rubbed or cut out promptly, and on own-root trees a regular programme of sucker removal keeps the stool from spreading into a thicket. Harvest runs from late August into October depending on form and season; fruit for cooking can be picked slightly underripe, while fruit for eating fresh should be fully softened and sweet, and handled gently as the skins bruise easily.

Common Problems

Silver leaf disease (Chondrostereum purpureum) is the most damaging fungal problem, entering through wounds and producing a characteristic silvery sheen on the foliage before dieback sets in. Pruning in summer, painting larger cuts and removing infected wood well below the discoloured zone are the standard responses. Bacterial canker (Pseudomonas syringae) causes sunken oozing lesions and dieback; affected wood should be pruned out in dry weather with tools disinfected between cuts.

Brown rot (Monilinia species) rots ripening fruit on the tree, producing concentric rings of buff-coloured spores; infected fruit should be removed and destroyed rather than composted, and any mummified fruit left hanging from the previous season cleared in winter. Plum moth (Grapholita funebrana) is a widespread pest, the caterpillars tunnelling into fruit and causing premature drop; pheromone traps hung in May help time control measures, and prompt removal of fallen fruit reduces the population for the following year. Leaf-curling plum aphid and mealy plum aphid distort young foliage in spring and early summer, and scale insects can weaken trees through sap-sucking and honeydew deposits, which in turn encourages sooty mould. Blackbirds and starlings will take ripening fruit from late July onwards, and netting is usually the only fully effective protection; fruit cages are worthwhile on isolated garden trees.

Popular Varieties

Cultivars within this subspecies are not as numerous as those of the garden plum, and several names that circulate informally are either synonyms or regional landraces of uncertain standing. The following are well-established and widely available in the UK.

• 'Merryweather Damson' — A vigorous, heavy-cropping damson producing large, round purple fruit with a comparatively sweet flavour; partly self-fertile and reliable in cooler districts.
• 'Shropshire Prune' (sometimes 'Damson Prune') — The traditional Shropshire damson: small, oval, very dark fruit with a sharp, intense flavour, considered the classic for jam and damson cheese.
• 'Farleigh Damson' — A compact, heavy-cropping form with small, deep blue-purple fruit; suitable for smaller gardens and exposed sites.
• 'Bullace' (Sheffield or White Bullace) — Round, late-ripening fruit in pale yellow-green, sharper than damsons; traditionally gathered from old hedgerows.
• 'Mirabelle de Nancy' — A small, yellow-green mirabelle-type plum, sweet and aromatic, widely grown in France for jam, tarts and liqueurs; crops well in southern and central England.

Pests and Diseases

For step-by-step help, read Controlling Aphids Naturally. Or browse the full plant problem solver to diagnose an issue by symptom.