Damson plum

Family

Rosaceae

Habit

Tree

Height

5 m

Spread

7 m

Growth

medium

Lifespan

50 years

First yield

after 4 years

Yield per plant

up to 40 kg a year

Hardiness

zone 4–9

Shade tolerance

full sun

Soil

Sand, Silt, Loam, Clay

Soil moisture

dry – moist

pH

6 – 7.5

Times apply to the northern hemisphere in a temperate climate and shift with altitude and cultivar.

Edible: The fruits are round to roundish, blue with a thin bloom, some 1.7 to 2.7 centimetres across and 6 to 8 grams in weight, with fairly firm flesh and a stone that does not part from it. They ripen between early and late September. How they taste depends on the type: hafer plums are low in tannin and can be eaten fresh, hafer sloes taste bitter and become palatable only through processing or frost, zibarten are yellow-green and similarly astringent. A particular quality is their keeping: the fruits dry in the open air without rotting, and in Provence they are peeled, stoned and traded as prunelles or brunelles. They also make purée, cake toppings and spirit. A tea is prepared from the flowers and leaves.

Medicinal: Little of medicinal substance is recorded for the damson itself. A tea of flowers and leaves is traditional, as known in Provence; there is no clinical evidence for it, and since the leaves contain cyanogenic glycosides, larger quantities are inadvisable. Dried fruits act as a mild laxative like other prunes — the effect comes from sorbitol and fibre rather than any single compound. The tannin-rich types taste astringent, which folk medicine employed against diarrhoea. The stone does not part from the flesh; bitter-tasting kernels contain amygdalin and do not belong in the kitchen. The flesh of the fruit itself is harmless.

Other uses: The greatest importance of this group lies outside the fruit bowl: the St. Julien rootstock derives from it, is documented in use for plums and quetsches since 1869, and remains among the most important rootstocks for light soils and unirrigated plantings. Its vigorous root suckering suits it to stabilising banks and building impenetrable shelter and windbreak hedges in the open landscape. The wood is hard and used in small turnery. Its taxonomic position remains disputed: in 1958 Werneck placed the hafer sloe closer to the blackthorn than to the kriecherl types, and it was formerly known simply as the tame sloe tree.

Site: The decisive factor is its urge to spread. The damson suckers vigorously and builds a thicket over the years — so it belongs in free-growing hedges, along boundaries and in orchard meadows, not in a narrow bed beside the terrace. Where space is limited, a root barrier or annual removal of the suckers helps. Two- and three-year-old shoots occasionally carry stout thorns, worth bearing in mind beside paths and seating. It needs no pollination partner: the cultivars are self-fertile. Keep a distance from commercial orchards, since like all plums it can host sharka disease. Care: It is decidedly easy-going and needs no regular pruning; thinning every few years keeps the shrub airy and forestalls fungal attack. Prune in summer after harvest rather than in winter — the wounds close faster and no gum exudes. The fruits ripen between early and late September and sit even on older, thicker branches inside the shrub, which makes picking a little laborious. One advantage of the old types: the fruit is usually free of maggots. Voles go for young roots, so a wire basket at planting is worthwhile.

The damson is one of the few plums that need not be grafted: it throws plenty of root suckers, which can be lifted in winter and replanted directly — the traditional route by which this group has maintained itself in hedges and cottage gardens for centuries. Plants raised this way come true and stand on their own roots. Sowing is possible, the stones requiring cold moist stratification over winter, but seedlings come out variable and serve mainly for raising rootstocks. That is the group's second significance: the St. Julien rootstock derives from it, has been used for plums and quetsches since the nineteenth century, and proves itself especially on light soils.

The early, abundant blossom in April supplies wild bees, bumblebees and honeybees with nectar and pollen at a time when little else is available; the flowers are openly built and accessible to insects of every tongue length. Its greatest value, though, is structural: the dense thickets built from root suckers make excellent nesting and shelter habitat for hedgerow birds such as red-backed shrike, whitethroat and yellowhammer, which seek out precisely such impenetrable scrub. The blue fruits are taken by thrushes, starlings and corvids, and windfalls are used by hedgehogs, foxes and insects. As a relative of blackthorn and plum it also feeds numerous moth and butterfly caterpillars.

Special features: ancient companion of cultivation, established in Central Europe longer than quetsche+plum; pentaploid chromosome set; German name Krieche→"kriechen" = strong root suckering; Hartmann grouping: hafer plum(sweetish, low tannin), hafer sloe(bitter), zibarte(yellow-green), St. Julien(rootstock, France); self-fertile; fruit 1.7-2.7cm, 6-8g, clingstone; usually maggot-free; dried prunelles(Provence); 3-4(-7)m; shoots mostly thornless, occasional stout thorns;

Western Asia, present in Europe since prehistoric times. The damson is the westernmost group of the plum relatives and takes its name from Damascus, by way of which it reached the Mediterranean — hence the English name. In Central Europe it has been established longer than the quetsche and the plum; finds document it here before either was introduced. Old populations centre on the Vosges, the Black Forest, the Swabian Alb and the Lake Constance region, where the group has been studied in detail. In France the St. Julien rootstock arose from it, and in Provence the dried fruits are traded as prunelles. It occurs naturalised in hedges and on field margins.

As an old companion of cultivation the damson belongs to the half-open landscape: to hedges, field margins and waysides, to orchard meadows and woodland edges. Because it suckers strongly from the roots it builds up whole clumps and dense thickets over time — unlike the cherry plum, which only throws shoots from the trunk. It is less demanding than quetsche or plum and copes with poor, stony and shallow soils and with rough uplands; on deep, nutrient-rich ground it simply grows more vigorously. Full sun to light partial shade suffices. It avoids waterlogging.