Sourplum refers to a diverse group of small, tart fruits from various botanical families. These fruits are characterized by their distinctly sour taste, making them a unique addition to culinary applications. The term “sourplum” encompasses several distinct species, each with its own characteristics and growing conditions.
Understanding Sourplum Varieties and Characteristics
Several plant species are known as “sourplum,” each with unique botanical origins and attributes. Ximenia americana, often called hog plum or wild plum, is found across tropical regions of Africa, India, Southeast Asia, and the Americas. This plant grows as a shrub or small tree, typically 2 to 7 meters tall. Its branches can be thorny, and its leaves are alternate, lanceolate to elliptic. The fruit is a globose to ellipsoidal drupe, about 3 cm long, turning from green to yellowish or orange-red when ripe, containing a juicy pulp, one large woody seed, and an “almond-acid taste.”
Another prominent “sourplum” is the Marula, Sclerocarya birrea, a deciduous African tree. This medium to large tree can reach heights of 9 to 18 meters, featuring a rounded, spreading crown and grey, cracked bark. Its leaves are large and compound. The Marula fruit is an obovoid, fleshy, and juicy drupe, 2 to 3.5 cm in diameter, ripening from green to yellow. The fruit’s pulp surrounds a hard stone containing two oily seeds, and it has a delicate nutty flavor.
Certain Prunus species are also referred to as sourplums, particularly Prunus mume, commonly known as Japanese apricot or Chinese plum. This deciduous tree typically grows 4 to 10 meters tall. Its leaves are oval-shaped with a pointed tip, appearing after the flowers. Prunus mume produces small, yellow-green to yellow plums that are aromatic and distinctly sour and tangy, often described as a cross between a plum and an apricot. These fruits are fuzzy-skinned and round, measuring about 1 to 1.25 inches in diameter with a clinging stone.
Cultivating Sourplum Trees
Cultivating sourplum trees requires understanding their specific environmental needs. Ximenia americana thrives in tropical and subtropical climates (USDA Zones 9-11), showing high drought tolerance and heat resistance. This species adapts to a wide range of soil types, including sandy, rocky, and nutrient-poor conditions, preferring well-draining soil and tolerating saline environments. It requires full sun. Planting fresh seeds can lead to germination within 14 to 30 days, with the plant growing moderately.
The Marula tree (Sclerocarya birrea) also prefers warm, frost-free conditions and tolerates a wide range of rainfall (200 to 1500 mm annually). It grows well in well-drained soils and can tolerate saline conditions and seasonal waterlogging. Marula trees require bright, direct sunlight, needing watering when the soil is almost completely dry. Propagation can occur from seeds or cuttings, with trees beginning to produce fruit as early as 5 years old.
Prunus mume, or Japanese apricot, is suited for USDA Hardiness Zones 6-9, requiring full sun to partial shade. This species prefers well-drained, fertile soil with a neutral to slightly acidic pH. Consistent moisture is important, especially during establishment, with deep watering allowing the soil to partially dry between sessions. Minimal pruning is generally needed, primarily to remove dead or diseased branches, and should be done in late winter or early spring or after flowering. Aphids and borers can be potential insect pests, while diseases such as silver leaf, blossom wilt, and bacterial canker may affect Prunus mume.
Culinary Uses and Nutritional Value of Sourplum
Sourplums are versatile fruits suitable for various culinary applications due to their notable tartness. They can be consumed fresh, used in jams, jellies, sauces, beverages, and incorporated into desserts.
For example, Prunus mume fruit is commonly pickled, used in juices and sauces, or dried, and is a popular flavoring for alcohol in East Asian cuisine. The Marula fruit is eaten fresh or boiled to flavor porridge, and it can be fermented into alcoholic beverages.
Beyond culinary uses, sourplums offer significant nutritional benefits. They are rich in vitamins, especially Vitamin C, with Marula fruit containing a higher concentration of Vitamin C than oranges. Sourplums are also sources of Vitamin K, copper, dietary fiber, and potassium, while being low in calories and saturated fats.
The fruits are packed with antioxidants, which help protect cells and support the immune system. Flavonoids and phenolic compounds contribute to these antioxidant properties and can aid digestion and boost metabolism. Ximenia americana has been used in traditional medicine for various ailments, including digestive issues, fever, and headaches. The high fiber content also supports digestive health.