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 Apricot

General Information

Prunus mume is a deciduous tree with a rounded crown, occasionally no more than a shrub; it usually grows around 4 - 10 metres tall[, ].
The plant is harvested from the wild for local use and trade as a food, medicine and source of materials. It is much cultivated in China and Japan for its edible and medicinal fruit (known as 'umboshi'), and is also widely grown as an ornamental[].
There is currently insufficient information available to evaluate this species. Although it appears relatively widespread in eastern Asia there is a lack of information regarding its population distribution, size and trend. The plant is classified as 'Data Deficient' 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 - Chine (Sichuan, Yunnan), Japan, Korea, northern Laos, northern Vietnam.

Habitat

Thickets in western China; at elevations from 300 - 2,500 metres[]. Forested slopes, beside streams, slopes along trails, sparse forests, mountains at elevations of 1700 - 3100 metres[].

Properties

Conservation Status	Data Deficient
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Deciduous Tree
Height	6.00 m
Pollinators	Insects
Cultivation Status	Cultivated, Ornamental, Wild

Cultivation Details

Prunus mume is cold-hardy to about -15°c when dormant[], though the blossom and young growth is susceptible to frost damage. In areas subject to late frosts it will often succed when grown against a sunny wall or in a sheltered woodland[].
Generally requires a sunny position and a sheltered site, though in areas with hot summers it appreciates some afternoon shade[, ].Thrives in a well-drained moisture-retentive loamy soil, growing well on limestone[, ]. Prefers a somewhat acid soil[]. Prefers some lime in the soil but is likely to become chlorotic if too much lime is present[].
This species is much cultivated, especially in China and Japan, for its edible fruit, there are many named varieties[, , ]. There are also forms developed as ornamentals[].
White-flowered forms possess a sweet perfume, but red-flowered forms have no scent[].
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[, , , ]. Preserved by salting or drying and eaten more as a vegetable than a fruit[]. Hard and sour even when fully ripe, it is scarcely edible[, ]. It is, however, widely used in the Orient where it is usually pickled and then used as a condiment and a vegetable[, ]. This is the umboshi plum that can be found in oriental stores. It is preserved in salt and used as a relish in rice dishes etc[].
Unripe fruits are processed to make a refreshing beverage; they are also used to make a special liqueur known as 'ume shu'[].
The fruit contains about 0.9% protein, 18.9% carbohydrate, 0.6% ash, no fat.The yellowish to greenish white, globose fruit is around 20 - 30mm in diameter and contains one large seed[, , ].

The flowers are used as a flavouring in tea[, ].

Seed - raw or cooked. The seed is rich in oils and protein[]. Do not eat the seed if it is too bitter - see the notes above on toxicity.

Young budlings[]. No more details are given.

The plant is used as a beverage base for human consumption[].

Medicinal

The unripe fruit is antibacterial, antipyretic, antispasmodic, astringent, carminative, cholagogue, pectoral, sialagogue and vermifuge[, , , , , ]. The fruit has a broad-spectrum antibacterial activity[]. Cooling and refreshing, it is mixed with other herbs and used internally in the treatment of bronchitis, chronic coughs, chronic diarrhoea and roundworms[, , ]. The fruit is also used in the treatment of diarrhoea and dysentery, to stop bleeding and to ease coughs[].
Externally, it is applied to fungal skin infections, corns and warts[].

The half-ripe smoked fruit is considered to be antispasmodic, carminative and febrifuge[].

Medicinal potential lies in developing an oral antimicrobial agent to control or prevent dental diseases associated with certain oral pathogenic bacteria, and it may also inhibit bacteria associated with gastritis and gastric ulcers[].

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 species is utilized for environmental improvement[].

Other Uses

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

An oil obtained from the seed is suitable for use in light industry[].

The plant is used for the production of beads[]. This probably refers to the seed[].

This species is a secondary genetic relative of the Apricot (Prunus armeniaca) and so it has the potential for use as a gene donor for crop improvement, including for traits which confer disease resistance[].

The wood is of high quality, but is generally too small for commercial use[].

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.