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: Pacific Plum

General Information

Prunus subcordata is a deciduous shrub or a tree, sometimes thorny, growing 1 - 3 metres tall, occasionally reaching 6 metres. Often suckering, the plant can form thickets[, ].
The plant is harvested from the wild for local use as a food. It is sometimes cultivated for its fruit, and is also grown as an ornamental[].
Prunus subcordata is thought to be stable across its native range in the US states of California and Oregon. 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

South-western N. America - Oregon, California.

Habitat

By streams, on dry hillsides and in open pine forests[, ]. Stream banks, dry rocky slopes, chaparral, pine-oak and juniper-oak woodlands; at elevations from 100 - 1,900 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

Thrives in a well-drained moisture-retentive loamy soil, growing well on limestone[, ]. Prefers some lime in the soil but is likely to become chlorotic if too much lime is present[]. Requires a sunny position[, ].
Occasionally cultivated for its edible fruit, there are some named varieties[]. The plant is also grown as an ornamental[].
Prunus subcordata shows variation in color, size, indument, and palatability of fruits, which has been the basis for recognition of taxonomic segregates. Variety kelloggii was described as a larger plant with less hairy foliage than in typical P. Subcordata, and its fruits are yellow, larger, sweeter, and more pulpy. Variety rubicunda is a smaller shrub with bright red, bitter fruits. Most noteworthy is var. oregana with densely hairy ovaries and puberulent fruits, recorded only from the sparsely inhabited border region between northeastern California and adjacent Oregon[].
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 in pies, preserves etc[, , , , ]. Pleasantly acid, the best forms have a slight astringency that imparts a distinctive flavour to culinary products made from the fruit[]. Considered to be one of the best flavoured wild fruits of Pacific N. America[]. The fruits are sourish, clingstone to freestone and are stewed or processed to sauces.The native tribes used the collected fruits as an ingredient of "pemmikan", their traditional, non-perishable food[]. The yellow to red, oblong fruits are 12 - 30mm 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[].

Other Uses

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

Prunus subcordata belongs to the tertiary Gene Pool of the cultivated Plum (Prunus domestica) and so it has the potential for use as a gene donor for crop improvement[].

Seedlings are sometimes used as a rootstock for plums[].

Wood - heavy, hard, close grained[]. The trees are too small for the wood to be of commercial interest[].

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.