Plant of the Month: March

Prunus spinosa Common name: Blackthorn, sloe Family: Rosaceae Vital statistics Height and spread: 5m (15ft) x 4m (12ft). Form:  Deciduous shrub Soil: Any, provided not waterlogged. Aspect: Full sun. Hardiness:  Fully hardy.

Prunus spinosa @ Rosemoor

This native hedgerow plant grows in abundance in mixed hedges in Devon and we have a number of good plants growing in the hedges throughout Rosemoor.

Prunus

Prunus is the Latin name for plum or cherry. This genus of over 200 species of deciduous or evergreen shrubs or trees is widely distributed in northern temperate regions and south to the mountains of S E Asia and the Andes in South America. It is usually found in woodland and in some other habitats including cliffs and coastal sands.

They are grown mainly for their flowers and autumn colour, also sometimes for their interesting bark and fruit.

All Prunus have alternate, oval to oblong leaves which are usually toothed. The flowers are white, pink or sometimes red, saucer-, bowl- or cup-shaped with five petals (more in the double or semi-double forms). Spherical or ovoid fruits usually follow the flowers, some of which are edible. However, leaves and fruits of most species may cause discomfort if ingested.

They make excellent specimen trees and many are suitable for small gardens. Some species are suitable for hedging.

Prunus spinosa

This species is found in Europe, North Africa and Western Asia and is a large, dense deciduous shrub or small tree. The bark is dark and the branches are spiny, hence spinosa.

The leaves are mid to dark green, up to 5cm (2in) long and elliptic to obovate in shape.

The flowers, usually solitary, are single and white, bowl-shaped and up to 1.5cm (0.5in) across and appear before the leaves in early and mid-spring.

The edible, spherical fruits are like small damsons, with a blue bloom at first and shiny black later, and up to 1.5cm (0.5in) across. The fruits are used in preserves and for making sloe gin.

The branches are made into walking sticks and the traditional shillelaghs from Ireland. The spines can be a problem in gardens as they can inflict wounds.

Prunus spinosa 'Purpurea' is a neat, compact bush with red leaves, later turning dark red-purple, and pale pink flowers.  P. spinosa 'Plena' has double flowers.

Cultivation

Grow in any moist but well-drained, moderately fertile soil in full sun.

Minimal pruning is required in late winter or early spring, to maintain a healthy framework. However, if silver leaf is a problem, prune in midsummer.

Prunus is susceptible to damage from aphids, caterpillars and bullfinches.

Diseases include silver leaf, honey fungus, blossom wilt and Taphrina wiesneri which causes witches broom (abnormal crowding of shoots).

Propagation

Sow seed of species in containers outdoors in autumn.

Root greenwood cuttings in early summer.

Bud cultivars in summer or graft in early spring.