Overview
Grewia micrantha var. concolor Chiov. is a species of flowering plant in the Malvaceae family, which is native to the East African region.
Common Names
This species is commonly known as sandpaper raisin, African star fruit, and mwinjilisti in the Swahili language.
Description
The sandpaper raisin plant is a small shrub or tree that grows up to 3 meters tall. The leaves are green, ovate, and serrated with a rough texture, which gives it the name sandpaper. The flowers are small, pale yellow, and fragrant, and produce a small reddish fruit that is edible and has a sour taste. The fruit looks like a tiny star-shaped capsule with 5 segments and can measure up to 1 cm in diameter.
Uses
The sandpaper raisin plant is highly valued for its medicinal properties as the bark, roots, and leaves are used to treat various ailments. It is believed to have antibacterial properties, and the roots are used to cure stomach ulcers. The bark is used to treat diarrhea, while the leaves help to relieve fevers and coughs. The fruits are also used to make jams and jellies during the fruiting season. The sandpaper raisin plant is also grown as an ornamental plant due to its attractive flowers and fruits.
Light Requirements
Grewia micrantha Bojer ex Mast. var. concolor Chiov. is a plant that requires full sun to partial shade for optimal growth. In areas with extremely high temperatures, it is recommended that the plant is grown in partial shade to protect it from scorching.
Temperature Requirements
The plant can grow in a wide range of temperatures but favors warm, moist climates. The ideal temperature range for growth is between 20°C to 30°C. The plant may not survive in areas with temperatures below 10°C.
Soil Requirements
Grewia micrantha Bojer ex Mast. var. concolor Chiov. prefers well-draining sandy loam soils that are rich in organic matter. It can also grow in other soil types with adequate drainage. Soil acidity should range between pH 5.5 and pH 7.0. The plant is native to Africa and is highly adapted to growing in poor soils.
Cultivation
Grewia micrantha Bojer ex Mast. var. concolor Chiov. grows well in various soil types, but well-draining, fertile soils are preferred. The plant prefers a sunny location but can also grow in partial shade. As a tropical plant, it requires warm temperatures and a humid environment to thrive.
Watering Needs
The plant needs regular watering, especially during the hot and dry seasons, to maintain healthy growth. It is important to avoid overwatering, as waterlogged soil can lead to root rot.
Fertilization
Grewia micrantha Bojer ex Mast. var. concolor Chiov. requires regular fertilization to promote healthy growth and flowering. The plant prefers a balanced fertilizer with equal parts nitrogen, phosphorus, and potassium. It is important to follow the manufacturer's instructions for application rate and frequency.
Pruning
Pruning is necessary to maintain the shape and size of Grewia micrantha Bojer ex Mast. var. concolor Chiov. The best time to prune is during the dormant season, typically in late winter or early spring. Remove any damaged or dead branches and thin out any overcrowded areas. It is important to use sharp and clean pruning tools to prevent the spread of disease.
Propagation of Grewia micrantha Bojer ex Mast. var. concolor Chiov.
Grewia micrantha Bojer ex Mast. var. concolor Chiov. can be propagated through various methods:
1. Seed propagation:
Seeds of Grewia micrantha Bojer ex Mast. var. concolor Chiov. can be collected from the plant during its fruiting season. The seeds should be cleaned and treated with fungicides before sowing. They can be directly sown in the soil or raised in a nursery. The seeds germinate in 2-3 weeks, and the seedlings can be transplanted after 4-6 months.
2. Vegetative propagation:
Grewia micrantha Bojer ex Mast. var. concolor Chiov. can be propagated vegetatively through the following methods:
a. Cuttings:
Semi-hardwood cuttings of Grewia micrantha Bojer ex Mast. var. concolor Chiov. can be taken during its active growth period. The cuttings should be about 25 cm long, with 2-3 nodes. The leaves should be removed from the lower half of the cutting, and a rooting hormone can be applied to the base. The cuttings should be planted in well-draining soil and kept in a shaded area. They should be watered regularly, and in 3-4 months, they will develop roots.
b. Air layering:
Air layering is another method for propagating Grewia micrantha Bojer ex Mast. var. concolor Chiov. In this method, a branch of the plant is chosen, and a slit is made about 15 cm from the tip. The slit is packed with sphagnum moss or vermiculite, and it is wrapped with plastic film to keep it moist. The branch is left for over a month, and roots will develop in the moss. The branch can then be cut off, and the rooted portion can be planted in a pot.
c. Grafting:
Grewia micrantha Bojer ex Mast. var. concolor Chiov. can be grafted onto a rootstock of its own species or another closely related species. Grafting is mainly done for improving the quality of the fruit or for disease resistance. The scion and rootstock should be of similar diameters, and the graft union should be protected with grafting tape. The grafted plant should be kept in a humid environment until the graft has taken.
Disease Management for Grewia Micrantha Bojer Ex Mast. Var. Concolor Chiov.
Grewia micrantha Bojer ex Mast. var. concolor Chiov. is susceptible to various diseases, and it is essential to manage them to achieve higher yields. Disease management involves cultural, chemical, and biological control methods.
Common Diseases and Their Management
Anthracnose: It is a severe fungal disease that affects the leaves, stems, and fruits of Grewia micrantha Bojer ex Mast. var. concolor Chiov. The symptoms include small, circular, water-soaked lesions that enlarge and become tan with a reddish-brown margin. To control the disease, remove infected plant parts, avoid overhead irrigation, and apply appropriate fungicides such as copper-based fungicides.
Root-Rot: This disease is caused by soil-borne fungi. It causes root decay and wilting of the plant, eventually leading to plant death. To manage this disease, avoid planting Grewia micrantha Bojer ex Mast. var. concolor Chiov. on poorly drained soil, maintain good plant nutrition, and apply appropriate fungicides such as metalaxyl.
Leaf Spot: The disease is prevalent during the rainy season, and it affects the leaves of the plant. The infected leaves develop small circular lesions with a yellow halo. To manage the disease, use clean planting materials, avoid overcrowding, and apply appropriate fungicides.
Pest Management for Grewia Micrantha Bojer Ex Mast. Var. Concolor Chiov.
Grewia micrantha Bojer ex Mast. var. concolor Chiov. is also affected by pests such as mealybugs, scale insects, and spider mites. Integrated pest management (IPM) strategies can help to manage these pests.
Common Pests and Their Management
Mealybugs: These pests are common in Grewia micrantha Bojer ex Mast. var. concolor Chiov. The symptoms are yellowing and wilting of the leaves. To manage this pest, prune the affected plant parts, use biocontrol agents such as ladybugs, and apply appropriate pesticides, such as neem oil.
Spider Mites: These pests appear as tiny yellow or green specks on the leaves, and they cause yellowing and wilting of the leaves. To manage this pest, increase the humidity around the plant, use biocontrol agents such as predatory mites, and apply appropriate acaricides such as abamectin.
Scale Insects: These pests feed on the sap of the plant, leading to yellowing and wilting of the leaves. To manage scale insects, prune the affected plant parts, use biocontrol agents such as parasitic wasps, and apply appropriate insecticides such as imidacloprid.
