Prunus japonica nakai - (Lév.)Rehder.

(Lév.)Rehder.

Japanese Plum

Rosaceae Edible: Fruit, Seed Potential hazards — see below

gbif· cc-by-nc

jung yong pak

gbif· cc-by-nc

jung yong pak

gbif· cc-by-nc

jung yong pak

Description

Prunus japonica nakai is an evergreen Shrub growing to 0.5 m (1ft 8in) at a medium rate. See above for USDA hardiness. It is hardy to UK zone 4. It is in flower in May, and the seeds ripen from July to August. The species is hermaphrodite (has both male and female organs) and is pollinated by Insects. The plant is self-fertile. It is noted for attracting wildlife. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils and prefers well-drained soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It prefers moist soil.

Edible Uses

Fruit - raw or cooked. A sweet agreeable flavour, they make a good pie. A very good size, about 50mm in diameter with one large seed. Seed - raw or cooked. Do not eat the seed if it is too bitter - see the notes above on toxicity.

Medicinal Uses

Aperient Aphrodisiac Carminative Demulcent Deobstruent Diuretic Lenitive Ophthalmic. The kernels are aperient, carminative, demulcent, deobstruent, diuretic, lenitive and ophthalmic[147, 176, 178, 218, 279]. Their use lowers the blood pressure. A decoction is used in the treatment of sluggish colon, constipation, oedema and inadequate elimination of urine. The pits of this sub-species are aphrodisiac for both sexes. The root is used in the treatment of constipation, children's fever, pinworms and teeth ailments. 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.

Known Hazards

Although no specific mention has been seen for this species, it belongs to a genus where most, if not all members of the genus produce hydrogen cyanide, a poison that gives almonds their characteristic flavour. This toxin is found mainly in the leaves and seed and is readily detected by its bitter taste. It is usually present in too small a quantity to do any harm but any very bitter seed or fruit should not be eaten. In small quantities, hydrogen cyanide has been shown to stimulate respiration and improve digestion, it is also claimed to be of benefit in the treatment of cancer. In excess, however, it can cause respiratory failure and even death.

Distribution

E. Asia - China, Korea, Manchuria.

Where It Grows

TEMPERATE ASIA: China Southeast, Korea, Manchuria,China North-Central.

Cultivation

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. A very ornamental plant, but it is subject to die-back. Plants in this genus are notably susceptible to honey fungus. This sub-species has larger plum-like fruits up to 50mm in diameter. Closely related to P. glandulosa. Most members of this genus are shallow-rooted and will produce suckers if the roots are damaged. A clumping plant, forming a colony from shoots away from the crown but with a limited spread. Harvesting typically occurs in late summer to early autumn, with specific timing varying by species. For instance, plums and peaches are usually harvested from July to September (Northern Hemisphere), while almonds are harvested in August to September (Northern Hemisphere). Prunus species usually flower in early spring, often between March and April (Northern Hemisphere), depending on the species and local climate. Growth rates vary among species, but generally, Prunus trees can grow moderately fast, often reaching full height in 3 to 5 years. However, they may take several years to bear fruit, depending on the species and growing conditions. Some Prunus species (like many plums and almonds) are self-fertile, while others (like sweet cherries and certain apricots) require cross-pollination with another compatible variety for optimal fruit set.

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, July/August in a frame. Softwood cuttings from strongly growing plants in spring to early summer in a frame. Layering in spring.