The White Raisin Bush (Grewia occidentalis) is a versatile plant, offering both ornamental beauty with its unique flowers and foliage, and edible, sweet fruits. Its adaptability to various growing conditions makes it appealing for gardeners seeking both aesthetics and utility in their outdoor spaces.
Understanding the White Raisin Bush
The White Raisin Bush (Grewia occidentalis) is also known as Crossberry, Lavender Star Flower, African Starbush, and Four Corners. Native to Southern Africa, it flourishes across diverse habitats in countries like South Africa, Zimbabwe, and Mozambique. It typically grows as a dense shrub or small tree, reaching 2 to 6 meters (6 to 20 feet) in height, and can sometimes exhibit a scrambling or climbing habit.
Its foliage features glossy, dark green leaves, ovate or elliptic with serrated edges, usually 3 to 7 centimeters long. Throughout summer, and sometimes year-round, the plant produces star-shaped flowers with five petals in shades of pink, lavender, purple, or white. These blossoms, 1.5 to 3.5 centimeters across, feature prominent yellow stamens. Following flowering, the plant develops fleshy, four-lobed fruits, which give rise to common names like Crossberry and Four Corners. Grewia occidentalis is hardy in USDA Zones 9 through 11, tolerating light frost.
Cultivating Your White Raisin Bush
Site Selection and Planting
The White Raisin Bush thrives in full sun, ideally receiving at least six hours of direct sunlight daily. It can also tolerate partial or afternoon shade. Due to its non-aggressive root system, Grewia occidentalis can be planted close to buildings or paving without concern for structural damage. When planting multiple bushes, space them 1.5 to 4 meters (5 to 12 feet) apart for adequate growth and air circulation.
Soil Requirements
The White Raisin Bush requires well-draining soil. It adapts to various soil types, including loamy and sandy, but flourishes in fertile, moist, and well-drained conditions. Incorporating organic matter like compost during planting enhances fertility and drainage. The plant tolerates a wide pH range, growing well in acidic, alkaline, or neutral soils.
Watering
Water the White Raisin Bush regularly, especially during establishment and dry periods. Allow the soil to dry out slightly between waterings to prevent oversaturation. While drought tolerant once established, prolonged dry conditions can stunt growth. During winter, particularly in cooler climates, reduce watering frequency as the plant may enter dormancy.
Fertilization
Apply a balanced fertilizer, such as a 10-10-10 formulation, to support healthy growth and flowering. During the active growing season (spring through summer), fertilize every 4 to 6 weeks. Alternatively, a monthly application of balanced liquid fertilizer or biannual feeding in spring and summer is sufficient. A late winter application of manure or compost also provides nutrients and improves soil structure.
Pruning
Pruning maintains the White Raisin Bush’s shape and size, encouraging vigorous growth and fruit production. The best time to prune is after flowering. Light pruning promotes a denser canopy, and the plant tolerates harder pruning for significant shaping. Remove dead, damaged, or errant branches to improve plant health. Encouraging lateral growth by selectively pruning strong vertical shoots can increase flowering and fruiting, and its flexible branches make it suitable for training as an espalier, a hedge, or ground cover.
Pest and Disease Management
The White Raisin Bush is resistant to common pests and diseases, making it a low-maintenance plant. It can be susceptible to glasshouse whitefly and red spider mites, particularly in protected environments. Caterpillars are also occasional pests. Regular inspection helps detect problems early for timely management.
Harvesting and Enjoying the Fruits
The White Raisin Bush fruits are four-lobed, initially green, transitioning to yellow, then to reddish-brown or light purple as they ripen. These fleshy, sweet berries are 1 to 2.5 centimeters across. In their native regions, ripening occurs from January to May, and fruits can remain on the tree for extended periods after maturity.
Harvest fruits when they develop their reddish-brown or purple color, indicating ripeness. The edible berries can be enjoyed fresh and raw. Historically, these fruits were collected and dried, or boiled in milk for a “bush milkshake.” They can also be used to brew traditional beers, or incorporated into jams, marmalades, or mixed with goat’s milk for a type of yogurt. The plant’s star-shaped flowers are also edible and can add a unique touch to salads.
The White Raisin Bush offers ornamental appeal, with its flowers and fruits providing year-round interest. It attracts local wildlife, including butterflies, bees, and birds, which feed on its nectar and berries. Its wood has been historically used for crafting items like bows and spear shafts, showcasing its versatility beyond edible fruits.