Prunus pumila Seeds | Sand Cherry
LATIN NAME: Prunus pumila
COMMON NAME: Sand Cherry
Plant Profile
Ask most people to picture a cherry and they describe a small tree in flower. This one refuses the picture. Prunus pumila is a low, sprawling shrub that runs over open sand by underground stems and by shoots that root wherever they touch, so that a single plant becomes a loose thicket of twiggy stems no taller than your knee in the most exposed forms. On the dunes of the Great Lakes the prostrate variety lies almost flat against the slope. On the deep sands of Nebraska and the Dakotas the western form stands up to a couple of metres and carries a crop of firm, dark cherries.
The difference in habit is not fashion. Burial by blowing sand is normal on these sites, and a plant that answers a fresh layer of sand by sending up new shoots survives a dune that would smother a tree. The sand cherry built its whole existence around ground that is dry, shifting and poor, and everything else about it follows from that.
Botanists divide the species into varieties rather than species, and the two that matter to growers are distinct in the garden. The lakeshore form keeps its stems close to the ground and works as a spreading cover on sand. The western form, named for the botanist Charles Bessey, is a taller, stiffer shrub with grey-green foliage that has been used for a very long time as hardy planting stock. Both make more new wood each season from the base than from the tips, which is the key to managing them.
Because the species roots readily and carries exceptional cold tolerance, it has been taken into culture: axillary shoots proliferate well from nodal pieces on a standard woody-plant medium, and the resulting plants are uniform enough for rootstock trials. More importantly, sand cherry has been crossed with peach and with cultivated cherries to move hardiness into the orchard, and prairie selections such as the Manitoba cultivar Manor have been grown for their own fruit rather than as stocks. Western sand cherry remains a standard dwarfing rootstock for cold-climate peach and plum plantings.
Science & Biotechnology
The kernel holds prunasin and amygdalin, the cyanogenic glycosides that the whole stone-fruit genus uses as a chemical defence. Chewing the kernel releases hydrocyanic acid, which is why the pits are never eaten and why browsing livestock leave the twigs alone once they have learned the taste. The flesh of the fruit carries no such charge. Anyone processing sand cherries for jelly should keep the stones out of the pot, for flavour as much as for safety, since the kernel is bitter as well as toxic.
Uses & Benefits
The leaves are narrow and short, seldom more than six centimetres, with fine teeth along the margin and a pale underside. They open with the flowers, which come in small clusters of two to four and are white, five-petalled and barely wider than a thumbnail. The fruit is a round drupe, dark purple to nearly black, with a firm skin and a stone that clings to the flesh; the flavour is sharp and winey when fully ripe, which is exactly what makes it worth cooking. The shrubs sucker freely, and one seedling will eventually spread into a patch several metres across.
The fruit is the point of the plant in the kitchen. Pick it fully dark and slightly soft, simmer it with a little water until the flesh gives, strain the juice through cloth without pressing the stones, and set it as a jelly; the result is deep red and tart, closer to a currant than to a sweet cherry. The firm flesh also holds up in pies and in a spiced preserve, and the fruit freezes well. Beyond the kitchen the shrub earns its place as a low windbreak on open ground, as nesting cover for birds, and as a sand-binder: the prostrate form has been planted widely on Great Lakes dunes precisely because it holds the surface while taller vegetation establishes.
Growing from Seed
Work with the plant’s preferences. A bed of three parts coarse sand or fine grit, two parts loamy topsoil and one part leaf-mould suits it far better than a rich border, and it will not tolerate wet, heavy soil at all. Clean the flesh from the stones, then sow them about a centimetre and a half deep in autumn, in a frame that gets full sun. A cold, damp winter rest is needed before the stones will wake. Space the shrubs a metre and a half apart in a fruit row, and about sixty centimetres apart if the aim is a dune-holding mat.
Water deeply in the first two seasons and then leave the plants alone; established sand cherries are drought-tolerant and dislike coddling. Feed nothing more than a light dressing of compost in spring. Cut the oldest canes back to ground level after the fruit is gathered, because the best crop sits on young wood. Watch for black knot, the dark, lumpy growth that affects the genus and should be cut out cleanly, and for curculio damage on the young fruit; deer will browse the stems hard in winter wherever the ground is open.
Our Take
Start the stones as soon as the fruit is eaten, and let the weather do the work of the cold rest; the shrubs transplant badly once the taproot has run, so move them small or sow them where they are to stay. If you want a taller cherry for the same cold, dry site, the shrubby Nanking cherry is a natural companion and is described in Prunus tomentosa. For a traditional European cherry grown for its stones rather than its flesh, see Prunus mahaleb, and for the orchard fruit that benefits from sand-cherry hardiness in its pedigree, read the practical notes on Prunus persica. Between them these four cover almost every dry, cold garden.
Related Reading
If Sand Cherry appeals to you, these related plants are worth a look: