Opinion has varied as to whether Prunus pumila is best treated as one variable or as two, three, or four separate species. The plants vary in stem posture, twig indument, leaf shape, fruit size and taste, pit size and shape, and ecologic preference. Even though the morphologic characters show almost continuous variation, four varieties are recognized here based largely on differences in ecologic habitat and geographic range[].
The taxonomic history of Prunus is long and complicated, in part due to the economic value of its fruit crops and also the ease with which some species hybridize. Here, Prunus is circumscribed in its broad sense based on the argument that when viewed on a worldwide scale, the morphologic discontinuities among the segregate genera diminish and they overlap with one another. Included here are species that have at times been placed in the genera Amygdalus, Armeniaca, Cerasus, Laurocerasus, Padus, and Persica.
At the species level, Prunus has been the object of the usual combining and splitting common among taxonomists with different philosophies and opinions. In particular, over-reliance on the indument of various vegetative and floral parts has led to the naming of numerous species and infraspecific taxa. Similarly, too much has been made of fruit colour and palatability in naming taxa of Prunus. It is very likely that, as molecular and genetic data are analyzed and, more importantly, correlated with morphological data, circumscriptions will be redrawn and the number of Prunus species will be reduced[].

Common Name: Western Sand Cherry

General Information

Prunus pumila besseyi is an unarmed, deciduous shrub, usually erect-ascending, sometimes sprawling with ascending tips; it usually grows 10 - 70cm all, occasionally reaching 150cm[].
The plant is harvested from the wild for local use as a food. It is sometimes cultivated for its edible fruit, and is also often grown as an ornamental. It is an excellent soil stabilizer and is used on dunes, roadside plantings etc.
Prunus pumila besseyi is widespread and largely secure across its native range in North America. However, it is classified as critically imperilled in much of its Canadian range, and there remains a lack of information regarding habitat trends and specific threats facing the species. The plant is classified as 'Least Concern' in the IUCN Red List of Threatened Species(2013)[].

Known Hazards

The plant (especially the seed and young shoots) contains cyanogenic glycosides, especially amygdalin and prunasin. When injested, these compounds break down in the digestive tract to release cyanide. Used in small quantities in both traditional and conventional medicine, this exceedingly poisonous compound has been shown to stimulate respiration, improve digestion, and promote a sense of well-being[]. It is also claimed by some to be of benefit in the treatment of cancer - though this claim has been largely refuted.
In larger concentrations, however, cyanide can cause gasping, weakness, excitement, pupil dilation, spasms, convulsions, coma and respiratory failure leading to death[].
The fruits and flowers of most members of this genus generally have low or very low concentrations of this toxin, though the seeds and young shoots can contain much higher levels.
The levels of toxin can be detected by the level of bitterness:- for example sweet tasting almond seeds are a major food crop and are often eaten in quantity, whilst bitter tasting almond seeds are used as a flavouring (in marzipan for example) but are not usually eaten on their own.
In general, it can be considered safe to eat any fruit or seed from species in this genus that either have a sweet flavour or are slightly bitter. Great caution should be taken, however, if the flavour is moderately to very bitter[].

Botanical References

, ,

Range

Central N. America - Saskatchewan to Ontario, south to Colorado, Kansas and Ohio

Habitat

Sandy hills, open plains, rocky slopes or shores[]. Sandy prairies, oak savannahs, rock outcrops; at elevations from 200 - 1,700 metres[].

Properties

Conservation Status	Least Concern
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Deciduous Shrub
Height	1.20 m
Pollinators	Insects
Self-fertile	Yes
Cultivation Status	Cultivated, Ornamental, Wild

Cultivation Details

Prunus pumila besseyi is a very hardy plant, probably tolerating temperatures down to about -50°c when it is fully dormant[]. It grows best in areas with hot summers and medium rainfall, it can flower very well in other parts of the temperate zone but does not usually produce much fruit[].
Requires a sunny position[]. Requires a well-drained moisture retentive soil[, ]. The plant grows in the wild on sandy, gravelly, and rocky soils, dunes, beaches, and outwash plains - sites are typically dry and excessively drained[]. Thrives in a loamy soil, doing well on limestone[]. Prefers some chalk in the soil but apt to become chlorotic if too much is present[]. Established plants are very drought resistant[]. Succeeds on calcareous, saline, or serpentine soils, tolerating a pH down to around 4.0[].
Prunus pumila besseyi is cultivated for its edible fruit in warmer regions of the temperate zone, and is also grown as an ornamental[, ], there are some named varieties[]. It has proved to be remarkably prolific on the hot, dry plains east of the Rocky Mountains in Colorado, Nebraska, Kansas, etc[].
The cultivar 'Black Beauty' crops well and has small black sweet fruits[]. 'Hansens' has large fruits with a good flavour[].
Prunus pumila is treated here as consisting of four more or less distinct varieties - each one is given a separate record because, amongst other differences, they vary in the size and quality of their edible fruit. Variety depressa always has prostrate to decumbent stems, and the plants form mats on the rocky or sandy substrate along streams in eastern North America. All of the other varieties sometimes have decumbent stems; specimens are sometimes misidentified as var. depressa, but nearly always some of the stems on these plants are ascending or erect. Stems of varieties besseyi and pumila are often partially buried in shifting sands on the dunes in the sandhills of Nebraska and on the dunes along the shores of the Great Lakes[].
Variety besseyi has been introduced west of its native range as an ornamental and fruit bearer for the home garden, where its adaptation to cold winters and hot, dry summers is a valuable asset. Cultivars were developed by breeders at the Morden Experimental Station in Manitoba and at the University of South Dakota[].
Most members of this genus are shallow-rooted and will produce suckers if the roots are damaged[]. Plants are inclined to sucker and can produce dense thickets[].
Plants in this genus are notably susceptible to honey fungus[].

Edible Uses

Fruit - raw or cooked[, , ]. A sweetish flavour, the fruit can also be dried for later use[]. It makes a rather astringent but tasty jelly[].The black, subglobose fruit is a reasonable size, around 8 - 18mm in diameter, and contains one large seed[, , ].

Seed - raw or cooked. Do not eat the seed if it is too bitter - see the notes above on toxicity.

Medicinal

Although no specific mention has been seen for this species, all members of the genus contain amygdalin and prunasin, substances which break down in water to form hydrocyanic acid (cyanide or prussic acid). In small amounts this exceedingly poisonous compound stimulates respiration, improves digestion and gives a sense of well-being[].

Agroforestry Uses:

The plant is considered to be a dune building species. It has a deep root network that helps to stabilize sand, allowing for the invasion of other plant species and colonization by 'soil building' invertebrates such as ants. It is most abundant on dunes 55 years old or less, and decreases in abundance as dunes age[].
It has been recommended for revegetation plantings in the Rocky Mountain and Intermountain west along road sides or other bare areas. It is listed as being high in value for restoration of disturbed sites for its soil stabilizing characteristics, and has been recommended for use in the revegetation of coal minespoils in the eastern United States primarily because of its tolerance of acidic soils[].

Other Uses

A green dye can be obtained from the leaves[].
A dark grey to green dye can be obtained from the fruit[].

Used as a rootstock for the sour cherry[]. It is a good dwarfing rootstock for peaches, apricots and plums[, ]. It produces mostly dwarf trees that are poorly anchored and prone to severe suckering[]. Compatible with most prunes, it is incompatible with damsons and Victoria plums[]. Resistant to 'Crown Gall'[]. Trees on this rootstock are productive and very cold hardy[]. Cuttings are often easy to root but seedlings vary widely[].

The plant (especially the var besseyi) has been used to create hybrids with the peach, apricot and plum. The resulting cultivars are generally quite winter hardy and bloom later in the spring which results in less spring freeze damage. Hybrids with the peach are largely sterile, but those with the Japanese plum are highly fertile[].

Propagation

Seed - requires 2 - 3 months cold stratification and is best sown in a cold frame as soon as it is ripe[]. Sow stored seed in a cold frame as early in the year as possible[]. Protect the seed from mice etc. The seed can be rather slow, sometimes taking 18 months to germinate[]. Prick out the seedlings into individual pots when they are large enough to handle. Grow them on in a greenhouse or cold frame for their first winter and plant them out in late spring or early summer of the following year.
Cuttings of half-ripe wood with a heel, mid summer in a frame[, ].
Softwood cuttings from strongly growing plants in spring to early summer in a frame[].
Division of suckers in the dormant season. They can be planted out direct into their permanent positions.
Layering in spring.