Chinese plum (Prunus salicina, Lindl. 1830)

Identity

Chinese plum (Prunus salicina Lindl., 1830), also known as Japanese plum, is a deciduous fruit tree in the genus Prunus, within the Rosaceae family. Despite the Japanese name, POWO places its actual native range in China, the Russian Far East, northern Vietnam and Taiwan, rather than Japan. ^{1 7}

The epithet salicina comes from the Latin salicinus, meaning “willowlike,” from Salix. It describes the elongated, finely toothed leaves, which visually resemble willow foliage more closely than the leaves of a European plum. ³

The name Japanese plum reflects its horticultural history: the species was grown in Japan for centuries before Japanese selections reached California in the late 19th century. Those introductions gave rise to most of the fresh plums sold in North America today. ²

Recognition

Wild trees reach 9–12 m (30–39 ft) tall, but annual pruning keeps most orchard trees at 3–5 m (10–16 ft). RHS gives 5–10 years as the time to full maturity for a compact cultivar such as Shiro. ^{2 3}

Oblong to obovate leaves measure 6–12 cm (2.5–5 in) long and 2.5–5 cm (1–2 in) wide. They have finely toothed edges and shiny, dark green upper surfaces. Young branches are purplish red and current-season shoots yellowish red, useful winter clues when flowers and foliage are absent. ³

Flowers open before or alongside the leaves in early spring. Each white flower is about 2 cm (0.8 in) across, with five petals; groups of two or three grow on one-year-old wood. Most cultivars are self-incompatible and need a second compatible Japanese plum nearby to bear fruit. ^{2 4}

The fruit is a drupe 4–7 cm (1.5–2.8 in) across, with yellow, red, green or purple skin beneath a fine waxy bloom, and juicy yellow-pink flesh. Ripening falls between late May and August in the Northern Hemisphere, depending on cultivar and climate. ^{3 4}

Useful taxonomy

For Chinese plum, the accepted botanical name in POWO is Prunus salicina Lindl. Older botanical and horticultural literature also contains several competing names:

• Prunus trifolia Roxb., an older name
• Cerasus salicina (Lindl.) Loudon, an older combination
• Prunus botan hort. ex Chow, a historical horticultural name
• Prunus salicina var. mandshurica (Skvortsov) Skvortsov & A.I.Baranov, a botanical variety name
• Prunus salicina var. pubipes (Koehne) L.H.Bailey, another botanical variety name

Four botanical varieties are recognized within the species: var. salicina, var. pubipes, var. mandshurica and var. cordata. This distinction matters because cultivar names such as Santa Rosa or Shiro do not correspond to these botanical varieties. They are horticultural selections assigned to the species. ¹

Habitat and range

From the Russian Far East through China to northern Vietnam and Taiwan lies the native range recorded by POWO for Prunus salicina. In China it grows in open forests, woodland edges, thickets and along valley streams at 200–2,600 m (650–8,500 ft) above sea level. ^{1 3}

Cultivation spread from this East Asian center to Korea and then Japan several centuries ago, before crossing the Pacific to California around 1870 and becoming established in Australia. In France, the species now represents about 25–30% of the land planted with dessert plums. ⁷

Orchard trees accept a broad range of soils, from sand and loam to clay, provided drainage is good. Waterlogged ground encourages root rot, a risk shared with other fruiting Prunus species, so soil texture alone does not determine whether a site is suitable. ^{3 2}

Life cycle and reproduction

A stone given 2–3 months of cold stratification can germinate, but seedlings do not reproduce the parent cultivar faithfully. Commercial fruit trees are therefore almost always grafted, preserving the selected fruit characteristics rather than relying on variable seedlings. ³

Early spring flowering precedes or accompanies leaf budbreak. A late frost of only −2 °C (28 °F) can destroy an entire display of blossoms and eliminate that year’s crop. Because most cultivars are self-incompatible, cross-pollination between two compatible Japanese plums remains necessary for good fruit set. ^{2 4}

Fruit then ripens through summer, but storage life is short: 3–4 days at room temperature or 1–2 weeks when chilled. This helps explain frequent processing into jam, fruit wine or dried preparations instead of prolonged storage on a shelf. ³

Uses and risks

Fruit production is the principal use: ripe flesh is eaten raw or cooked and made into jams and fruit wines. In East Asia, whole fruits also feature in candies or fruit liqueurs. ³

As with other stone-fruited Prunus, the essential distinction is that ripe fruit flesh is edible, but the whole tree is not. The ASPCA lists plum among plants toxic to cats, dogs and horses. ⁵

Cyanogenic glycosides occur in the stems, leaves and especially the stone, with danger increasing as foliage wilts. Reported signs following a concerning ingestion include brick-red mucous membranes, dilated pupils, respiratory distress, panting and shock. ⁵

After a substantial ingestion of foliage, twigs or broken stones, contact a veterinarian or poison control center and identify the species involved. Avoid attempting a home treatment when the amount or plant part raises concern. ⁵

Cultivars and related plants

Commercial Chinese plum cultivars are horticultural selections rather than botanical varieties. Santa Rosa, raised by nurseryman Luther Burbank, is often regarded as a flavor benchmark. Shiro bears golden-yellow fruit on a smaller tree; Methley is self-fertile with dark red fruit; Ozark Premier suits hot summers. ^{2 4}

European plum, Prunus domestica, is the most frequent source of confusion. It is hexaploid, whereas Prunus salicina is diploid, and its fruit is often more elongated and suited to drying as prunes. Chinese plum usually bears rounder fruit with smooth, bloom-covered skin. ¹

Cherry-plum, Prunus cerasifera, can also cause confusion. Often planted as a rootstock or flowering hedge, it bears much smaller fruit than cultivated Prunus salicina. For a young nursery tree, the botanical name and rootstock are the most reliable identification guides. ¹

Main sources

• Plants of the World Online / Kew, Prunus salicina Lindl.
• Royal Horticultural Society, Prunus salicina 'Shiro' plant details
• Plants For A Future, Prunus salicina
• NC State Extension Gardener Plant Toolbox, Prunus salicina 'Methley'
• ASPCA, Plum toxicity entry
• IUCN Red List, Prunus salicina assessment
• Integrated Taxonomic Information System, Prunus salicina Lindl., TSN 506232
• Wikidata, Prunus salicina (Q1250033)