The Crossberry plant, Grewia occidentalis, offers an intriguing addition to any garden. This versatile shrub captivates with its delicate flowers and unique fruits, making it a resilient and adaptable botanical specimen for various landscape designs.
What is Crossberry
Grewia occidentalis, commonly known as Crossberry, Four-cornered Berry, or Lavender Starflower, is a member of the Malvaceae family. This plant typically grows as a scrambling shrub or a small tree, reaching heights of up to 3 meters, though some specimens can extend to 6 meters. Its growth habit can be either deciduous or evergreen, depending on climate conditions.
The leaves are simple and alternate, shiny deep green with a slightly fleshy texture. They are usually ovate to ovate-lanceolate, measuring between 3 to 7 centimeters long and 2 to 4 centimeters wide, often displaying three distinct veins from the base. In summer, the plant produces attractive star-shaped flowers, typically 1.5 to 3.5 centimeters across, in shades of purple, mauve, pink, or occasionally white. These blooms are followed by the plant’s most distinctive feature: a four-lobed, or quadrilobed, drupe. These fruits transition from green to a shiny reddish-brown or light purple when ripe, often persisting on the plant for extended periods. The Crossberry is indigenous to Southern Africa, with a natural distribution spanning from the Western Cape to Mozambique and Zimbabwe. It thrives in a variety of natural habitats, including arid karoo, coastal dune bush, evergreen montane forests, and wooded grasslands.
Growing Conditions and Care
Crossberry performs best in full sun, requiring at least six hours of direct sunlight daily for optimal growth. It can tolerate partial shade conditions. Ample light supports robust development and abundant flowering.
Crossberry adapts to various soil types, including sandy, loamy, and clay soils, but it particularly thrives in fertile, well-draining loamy soil. Incorporating compost or other organic matter into the planting hole can significantly enhance its growth. Proper drainage is important to prevent waterlogged conditions, which can lead to root rot.
Once established, Grewia occidentalis exhibits good drought tolerance. Regular watering during dry spells promotes more vigorous growth. Allow the soil to dry out slightly between waterings to avoid over-saturation. The plant prefers moderate temperatures and can withstand some light frost, with mature plants tolerating short periods down to approximately -5°C, although foliage damage may occur at -2°C. Young plants benefit from protection during colder temperatures.
Pruning is beneficial for maintaining the Crossberry’s shape, size, and promoting new blooms. The ideal time to prune is after its flowering period. While it can tolerate hard pruning, light pruning encourages a fuller, denser canopy. Crossberry is robust and not frequently troubled by pests or diseases. Occasional issues like galls caused by insects such as wasps or aphids might appear. If grown in a greenhouse, it could be susceptible to glasshouse whitefly or red spider mite. Fertilization with a balanced fertilizer, such as a 10-10-10 NPK formula, every 4-6 weeks during the growing season encourages healthy growth and flowering.
Propagation and Harvesting
Propagating the Crossberry plant can be achieved through both seeds and cuttings. While seed propagation is common, successful germination can sometimes be unpredictable. Soaking seeds in water for two days prior to planting can aid the process. When sowing seeds, it is recommended to do so in spring, using a well-draining, aerated loam kept moist at temperatures between 24-28°C; germination typically occurs within 2 to 6 weeks.
Softwood cuttings are another effective propagation technique for Grewia occidentalis. These cuttings are best taken in spring or early summer from healthy, non-flowering stems, ideally 4-6 inches in length. Make a clean cut just below a node, remove the lower leaves, and consider dipping the cut end in rooting hormone to stimulate root development. Plant the cuttings in a well-draining potting mix, ensuring the soil remains consistently moist but not waterlogged. Provide a humid environment, perhaps by covering them with a clear plastic bag. Root formation can take several weeks to a few months.
Harvesting Crossberry fruits is straightforward once they reach maturity. The fruits typically ripen between January and May, transforming from green to a shiny reddish-brown or light purple color. At this stage, they become soft to the touch, indicating they are ready for picking. Gently pluck the ripe fruits from the plant to avoid damaging the branches or other developing fruits.
Uses and Benefits
The Crossberry plant offers a variety of uses and benefits. Its edible fruits have a sweet and tart flavor, suitable for fresh consumption or for making jams, jellies, and juices. Traditionally, dried fruits have been boiled in milk or fermented to produce a type of beer.
Beyond culinary uses, Grewia occidentalis provides ornamental value. Its attractive flowers, glossy foliage, and distinctive four-lobed fruits contribute to its appeal as a decorative garden plant. It can be used as a hedge, a standalone specimen, or integrated into mixed borders and screening. The plant’s flexible branches also allow for shaping into forms like topiary or espaliers. A practical advantage is its non-aggressive root system, making it suitable for planting near buildings or paved areas without concern for structural damage.
The Crossberry also supports local wildlife. Its flowers and fruits attract a variety of birds, including louries, mousebirds, bulbuls, and barbets, as well as butterflies, bees, and other pollinators. It serves as a larval host plant for specific butterfly species, such as the Rufous-winged Elfin and Buff-tipped Skipper. Historically, various parts of the plant have been utilized in traditional medicine for a range of purposes, and its wood has been used for crafting items like bows and spear shafts.