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: Japanese Plum

General Information

Prunus salicina is a deciduous tree that can grow 6 - 12 metres tall[, ].
The plant has a long history of cultivation as a fruit crop in China, and this cultivation has gradually spread to other warm temperate to subtropical regions of Asia. More recently cultivation has spread to Europe, Australia and the Americas[].
Wild populations are documented to be thriving in some areas of its range, suggesting the population is stable. It is also conserved both in situ and ex situ. 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

E. Asia - China, Myanmar, Laos, Vietnam

Habitat

Sparse forests, forest margins, scrub, along trails in mountains, beside streams in valleys, thickets; at elevations from 200 - 2,600 metres[].

Properties

Conservation Status	Least Concern
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Deciduous Tree
Height	8.00 m
Pollinators	Insects
Cultivation Status	Cultivated, Wild

Cultivation Details

Prunus salicina is fairly cold-hardy, tolerating temperatures in winter falling to -15°c or perhaps lower. However, it requires hot summers in order to ripen its wood and so often does not thrive in maritime and cool summer regions. It can also be excited into early growth in mild winter areas and is then susceptible to damage by late frosts[, ].
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[, ].
An important temperate fruit tree, it is widely cultivated in China and other regions of Asia for its edible fruit, and is being increasingly grown in N. America[]. There are several named varieties[, , ].
The cultivated Prunus salicina has several useful characters: an exceptional immunity to fruit rot, early fruit ripening and a unique taste. Yet its poor resistance to cold and early flowering limit its distribution in the USSR to the extreme southern regions, the Black Sea coast of the Caucasus, Transcaucasia, Lenkoran, and S. Central Asia[].
This species does not cross-pollinate with the English plum, Prunus domestica[].
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[, , , ]. The fruit ripens early[]. A unique taste[]. Sweet and juicy, it can be eaten out of hand, made into pies, preserves etc, or be dried for later use[]. The fruit is very resistant to rotting[]. The yellow, orange, red, sometimes green or purple, globose to ovoid fruit can be 35 - 70mm long 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

The fruit is stomachic[]. It is said to be good for allaying thirst and is given in the treatment of arthritis[].

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[].

Wild populations of this species are primary genetic relatives of the cultivated Japanese Plum (Prunus salicina) and they also belong to the secondary Gene Pool of the Apricot (Prunus armeniaca), Myrobalan Plum (Prunus cerasifera) and Peach (Prunus persica). As a result, this species has the potential for use as a gene donor for crop improvement[].

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.