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: Dwarf American Cherry

General Information

Prunus pumila is an unarmed, deciduous shrub wih stems that are usually erect-ascending, sometimes decumbent; it can grow 30 - 150cm tall, occasionally to 250cm[]. The plant sometimes produces suckers, and can form thickets[].
The plant is harvested from the wild for local use as a food. It is an excellent soil stabilizer and is used on dunes, roadside plantings etc. It is also used as a rootstock and in breeding programmes, especially with the Japanese plum.

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

Eastern N. America - Ontario to New York, south to Illinois and Pennsylvania

Habitat

Dunes and sand, or on calcareous rocky shores[]. Shores of the Great Lakes on sandy, gravelly, or rocky beaches, dunes, interdunal flats; at elevations from 70 - 200 metres[].

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Deciduous Shrub
Height	0.60 m
Pollinators	Insects
Self-fertile	Yes
Cultivation Status	Wild

Cultivation Details

This species is hardy to about -35°c when the plants are fully dormant[], though the young growth in spring is fairly tender[].
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 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 the 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[].
Plants are susceptible to mildew in low areas[].
Plants thrive in areas with a short growing season[]. The fruits are highly resistant to all fruit worms[].
Plants can produce fruit in 3 years from seed[].
A single plant, growing at Hilliers Arboretum in 1999, produced a good crop of fruit with viable seed, so the species is almost certainly self-fertile[].
Most members of this genus are shallow-rooted and will produce suckers if the roots are damaged[].
Plants in this genus are notably susceptible to honey fungus[].

Edible Uses

Fruit - raw or cooked[, , ]. A rich and pleasantly acid taste when fully ripe though they are sometimes slightly bitter[, , , ]. Eaten out of hand, used in preserves or dried for later use[]. A reasonable size, the black or purplish, subglobose fruit is 8 - 12mm in diameter with one large seed[, , ]. This is the largest of the N. American cherries[].

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[]

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[].
Layering in spring.