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: Hog Plum

General Information

Prunus hortulana is a moderately thorny, deciduous shrub, or more commonly a tree, usually growing 4 - 10 metres tall. The tree occasionally produces suckers[].
The tree is harvested from the wild for local use as a food and source of materials. It is often cultivated for its edible fruit, especially in eastern N. America and other areas with hot summers; is also sometimes grown as an ornamental; and is used as a rootstock and in breeding programmes[].
Prunus hortulana is a fairly widespread species and is apparently secure across its native range, despite being under threat in Iowa, Nebraska and Kansas. 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 and eastern N. America - Nebraska to Massachussetts, south to Oklahoma, Tennessee and Virginia

Habitat

Bottomlands, thickets and woodland edges[], in rich moist soils[]. Roadside thickets, flood plains, open woodlands; at elevations from 50 - 500 metres[].

Properties

Conservation Status	Least Concern
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Deciduous Tree
Height	7.50 m
Pollinators	Insects
Cultivation Status	Cultivated, Ornamental, Wild

Cultivation Details

Prunus hortulana is fairly cold-hardy, tolerating temperatures falling to around -15°c when dormant. It requires hot summers if it is to fruit well, and so generally does not thrive in mild, maritime areas[].
Thrives in a well-drained moisture-retentive loamy soil[, ]. Prefers some lime in the soil but is likely to become chlorotic if too much lime is present[]. Succeeds in sun or partial shade though it fruits better in a sunny position[, ].
The plant is sometimes cultivated for its edible fruit in Southern N. America, there are some named varieties[, , ].
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. Thin-skinned and fleshy[, ] with an agreeable flavour, it can be eaten out of hand or be made into pies, preserves etc[]. Another report says that it is small and not very palatable, and is only used in preserves[]. The globose, red to yellowish fruit has white dots; it is usually 20 - 30mm in diameter, occasionally reaching 40mm[, , ].

Flower buds[]. No more details are given.

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[].

Other Uses

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

This species belongs to the secondary Gene Pool of the Myrobalan Plum (Prunus cerasifera) and Japanese Plum (Prunus salicina). It also belongs to the tertiary Gene Pool of the Peach (Prunus persica), and so it has the potential for use as a gene donor for crop improvement, particularly to confer disease resistance to crops[].

The plant has potential for use as rootstock for the cultivated Peach (Prunus persica)[].

The wood is heavy, hard and strong. It is used for turnery[].

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.