Overview
Grewia gigantiflora K.Schum. is a tree species that belongs to the family Malvaceae. It is native to tropical and subtropical regions of Africa, including Angola, Cameroon, Democratic Republic of Congo, Gabon, Kenya, Malawi, Nigeria, Sudan, Tanzania, Uganda, Zambia, and Zimbabwe.
Common Names
The plant is commonly known by various names, including Giant Flowered Raisin, Giant Flowered Grewia, and Mukoma-koma in Kenya.
Appearance
Grewia gigantiflora is a medium-sized deciduous tree that can grow up to 20 meters tall. The tree trunk is usually straight, thick and covered in a greyish-brown bark that is rough to the touch and often exfoliating. The leaves are simple, alternate and ovate in shape, with a length of about 10cm and a width of about 6cm. The upper surface of the leaves is dark green, while the lower surface is silvery-grey.
The tree produces large (up to 12cm in diameter) mauve to purple flowers that are arranged in clusters at the end of the branches. The fruit of the plant is an edible berry that is about 2cm in diameter, yellow to brown in color and has a taste similar to that of a raisin.
Uses
The tree has several traditional and modern uses. The leaves, bark, and roots of the tree are used to treat various ailments, such as diarrhea, pneumonia, and rheumatism. The bark is also used to make medicinal tea that promotes digestion, lowers fever and acts as a sedative.
The fruit of the tree is edible and is a source of nutrition for humans and animals alike. In some regions, the fruit pulp is mixed with water to make a refreshing drink. The wood of the tree is hard and durable, and is used for making furniture, utensils, and tool handles.
Growth Conditions for Grewia gigantiflora K.Schum.
Grewia gigantiflora K.Schum., commonly known as giant-flowered grewia, is a deciduous shrub or small tree native to eastern Africa. It grows in a variety of habitats including forest edges, river banks, and rocky hillsides. Here are the typical growth conditions for Grewia gigantiflora K.Schum.:
Light
Grewia gigantiflora K.Schum. prefers partial to full sun exposure for optimal growth and flowering. In shaded areas, the plant may become leggy, weak, and produce fewer flowers.
Temperature
Grewia gigantiflora K.Schum. can tolerate a wide range of temperatures, but it thrives in warm and humid conditions. The plant grows best in areas with a temperature range of 20-30°C (68-86°F) and requires protection from frost as it is not frost-tolerant.
Soil
Grewia gigantiflora K.Schum. prefers well-draining soils that are rich in organic matter. The plant can tolerate a variety of soil types, including sandy, loamy, and clayey soils. However, it cannot tolerate water-logged soils or soils with a high salt content. A pH range of 6.0-7.5 is ideal for the growth of Grewia gigantiflora K.Schum.
With the right growth conditions, Grewia gigantiflora K.Schum. can be an attractive addition to any garden or landscape, providing a showy display of large, bright flowers during the growing season.
Cultivation of Grewia gigantiflora K.Schum.
Grewia gigantiflora K.Schum. is a evergreen shrub or small tree that grows up to 6 meters in height. It is native to Sub-Saharan Africa, where it thrives in warm, humid conditions. To cultivate this plant successfully, the following conditions must be provided:
- Well-draining soil
- Full sunlight or partial shade
- Regular watering
- Temperatures between 20°C to 30°C
Ensure the plant receives adequate sunlight, as this will influence the number of flowers produced. The soil should be a well-draining sandy or loamy soil with a pH between 6.5 and 7.5. Additionally, plant the shrub in areas that aren't susceptible to strong winds.
Watering Needs
Good soil moisture ensures optimal growth and healthy plants. Grewia gigantifolia K.Schum. requires regular watering to thrive. During the growing season, ensure the soil is moist, but not oversaturated. Overwatering can lead to root rot, which may damage the shrub's health.
Water the plant deeply and infrequently, only after the top of the soil dries up. During the dry season, water the plant regularly to maintain its health and prevent wilting.
Fertilization
Grewia gigantiflora K.Schum. requires adequate nutrition to promote healthy growth. Fertilize the plant during the growing season and provide a balanced fertilizer. For optimal results, use a slow-release fertilizer that provides nutrients gradually throughout the growth cycle.
Overfeeding the plant can lead to excessive growth, which may reduce the number of flowers produced. Therefore, ensure you apply fertilizer as recommended by the manufacturer to avoid overfeeding the plant,resulting in weak, leggy growth.
Pruning
Grewia gigantiflora K.Schum. requires minimal pruning. However, it's essential to prune the shrub to promote airflow, remove diseased or dead branches and promote a healthy shape. Prune the shrub after it has finished blooming.
Remove damaged or diseased branches using pruning shears. Additionally, cut back overgrown branches to maintain the shrub's shape and size. Prune the shrub lightly to promote flowering, as the shrub produces flowers on new growth.
Be careful not to over-prune the shrub, as this may result in a weak structure or reduced flowering.
Propagation of Grewia gigantiflora K.Schum.
Grewia gigantiflora K.Schum. is propagated through seeds, stem cuttings, and layering.
Propagation by Seeds
Seeds from mature fruits can be collected and kept in a cool, dry place until the planting season. The seeds are then sown in a well-drained nursery bed at a depth of 1-2 cm and covered with a thin layer of soil. The nursery bed should be watered regularly to keep the soil moist. Germination usually occurs within 4 to 6 weeks.
Propagation by Stem Cuttings
Softwood cuttings of G. gigantiflora can be taken during the growing season. The cuttings should be about 10 cm long and taken from healthy, disease-free plants. The lower leaves are removed, and the cuttings are dipped in rooting hormone before being planted in a rooting medium like sand or vermiculite. The cuttings should be kept in a well-lit and humid environment until roots have developed, usually within 4 to 6 weeks. Once rooted, the cuttings can be potted up individually and grown on until they are large enough to plant outdoors.
Propagation by Layering
G. gigantiflora can also be propagated by layering. A low branch can be bent down and pinned to the ground, and a small wound is made on the underside of the branch to encourage root growth. The area around the wound is then covered with soil, and the branch is kept in place with stakes or rocks. After a few months, roots should have developed, and the branch can be separated from the mother plant and planted in its own pot or in the ground.
Disease and Pest Management for Grewia gigantiflora K.Schum.
Grewia gigantiflora K.Schum., also known as Giant Star Hibiscus, is a hardy plant that can resist pests and diseases to some extent. However, it is still vulnerable to various pests and diseases that can harm its growth, productivity, and overall health. Therefore, proper management of these pests and diseases is essential to ensure the plant's well-being and longevity. Here are some of the common pests and diseases that affect Grewia gigantiflora and ways to manage them.
Pest Management
Aphids: Aphids are tiny insects that suck the plant sap from the leaves and stems of the Grewia gigantiflora plant, causing them to wilt or die. They also excrete a sticky substance on the plant surface, which attracts ants and other insects. To manage aphids, you can spray the leaves and stems with a solution of neem oil and water or insecticidal soap. You can also use natural predators like ladybugs and lacewings to control aphids.
Caterpillars: Caterpillars are the larvae of butterflies and moths that feed on the Grewia gigantiflora leaves, causing them to turn brown or wither. To manage caterpillars, you can pick them off by hand or use biopesticides like Bacillus thuringiensis (BT) that target only caterpillars, leaving other insects unharmed.
Spider Mites: Spider mites are tiny insects that feed on the plant cells, causing the leaves to turn yellow and fall off. They also produce a fine web on the plant surface, which makes it look unsightly. To manage spider mites, you can spray the plant with a solution of neem oil and water or use predatory mites like Phytoseiulus persimilis that feed on spider mites.
Disease Management
Anthracnose: Anthracnose is a fungal disease that affects the leaves and stems of the Grewia gigantiflora plant, causing them to develop brown patches or lesions. The disease spreads quickly in wet and humid conditions, making it difficult to control. To manage anthracnose, you can apply a fungicide that contains copper or sulfur compounds. You can also prune the infected parts of the plant and dispose of them properly to prevent the disease from spreading.
Powdery Mildew: Powdery mildew is a fungal disease that affects the plant's leaves and flowers, causing a white powdery substance to appear on the surface. The disease spreads quickly in dry and humid conditions, making it difficult to control. To manage powdery mildew, you can spray the plant with a solution of baking soda and water or apply a fungicide that contains potassium bicarbonate. You can also improve air circulation around the plant and avoid watering the leaves to prevent the disease from spreading.
In conclusion, proper management of pests and diseases is essential to ensure the health and productivity of the Grewia gigantiflora plant. By following the above-mentioned tips and adopting preventive measures, you can effectively manage pests and diseases and enjoy the beauty of this magnificent plant for years to come.
