Overview of Grewia arborea
Grewia arborea (Forssk.) Lam. is commonly known as the toothbrush tree, or locally referred to as "jojoba" in Ethiopia and "ngwaci" in Kenya. This flowering plant belongs to the family Malvaceae, and it is native to East Africa and parts of the Arabian Peninsula, specifically Djibouti, Eritrea, Ethiopia, Somalia, Kenya, Tanzania, Uganda, and Yemen.
Appearance of Grewia arborea
The toothbrush tree is a small to medium-sized tree, growing up to 20 m in height, with a single straight trunk that can have a diameter of up to 1 meter. The bark is greyish-brown, with small cracks and patches. The leaves are simple, alternate, and ovate, measuring between 2 and 8 cm long, with a serrated margin and pointed tip. The flowers are small and inconspicuous, greenish-yellow in color, and arranged in axillary clusters. The fruit is a small, round, and fleshy drupe, measuring between 6 and 10 mm in diameter, and can be red, yellow, or purple in color.
Uses of Grewia arborea
Grewia arborea has various uses in traditional and modern medicine, as well as several practical and ornamental applications, including:
- Leaves and bark are used to treat a variety of ailments, such as fever, diarrhea, dysentery, and respiratory infections.
- The fruit is edible, used in making jams, jellies, and beverages.
- The bark and wood are used for construction, fuel, and charcoal production.
- The roots, leaves, and stem bark are used for making ropes and baskets.
- The plant is also used as a hedge, windbreak, or shade tree, as well as an ornamental plant in gardens and parks.
Light Requirements
Grewia arborea prefers bright but indirect sunlight. It can tolerate partial shade, but too much shade can stunt its growth. The plant grows best in areas with at least six hours of sunlight per day.
Temperature Requirements
Grewia arborea grows well in warm climates. The plant prefers temperatures in the range of 20 to 30 degrees Celsius. It cannot tolerate frost or extremely cold conditions.
Soil Requirements
Grewia arborea grows best in well-draining and fertile soil. The plant prefers soil with a pH level between 6 to 7. The soil should be rich in organic matter and nutrients. Sandy loam soils can also be suitable for this plant. It is important to avoid waterlogged or poorly drained soil as it can cause root rot.
Cultivation of Grewia Arborea
Grewia Arborea, also known as Phalsa or Falsa, is a small deciduous tree that is cultivated for its delicious and nutritious berries. The plant is native to South Asia and is commonly found in India, Pakistan, Bangladesh, and Nepal. The following are some tips for cultivating Grewia Arborea:
- Plant the tree in well-draining soil that is rich in organic matter.
- Ensure that the soil is deep enough to accommodate the roots of the plant.
- Choose a location that receives full sunlight for optimal growth.
- Make sure that the temperature is warm and not below freezing temperature.
- Water the plant frequently during its initial growth stages until it is well established.
- Provide support when the tree grows tall enough to require it to avoid breaking.
Watering Needs
Grewia Arborea requires frequent and consistent watering during its growth stages. However, it is essential to avoid overwatering, which can lead to root rot and other plant diseases. The soil should be moist, but not saturated with water. A general rule of thumb is to water the plant every two days. But it is also advisable to adjust the frequency according to your climate and soil condition.
Fertilization
Fertilizing Grewia Arborea is crucial for optimal growth and fruit production. A balanced fertilizer is recommended to provide essential nutrients like nitrogen, phosphorus, and potassium to the plant. A suitable organic fertilizer like compost, cow dung, or poultry manure can also be used. Fertilize the plant quarterly, with the first application during the growing season's start and the last application after the harvest season.
Pruning
Pruning Grewia Arborea is essential for shaping the plant for easy harvesting, removing dead or diseased branches, and promoting new growth. Prune the plant during the dormant season in winter when it has already lost the leaves. Avoid pruning in spring and summer when the plant is actively growing. Use sterile pruning shears, cut at a 45-degree angle, and leave a little height from the bud to encourage new growth. Get rid of the pruned branches and dispose of them in yard waste bins or compost.
Propagation of Grewia arborea
Grewia arborea (Forssk.) Lam., commonly known as the Toothbrush tree, is a perennial plant that is native to the Indian subcontinent. It is a difficult plant to propagate as it has a low germination rate, long gestation period and requires special care during propagation to ensure good growth.
Propagation Methods
The following are the methods that can be used to propagate Grewia arborea:
Seed Propagation
The most common method of propagating Grewia arborea is through seed propagation. Seeds should be obtained from healthy plants and should be sown immediately after collecting them to prevent them from losing their viability. The seeds should be sown in a well-drained soil mixture of sand and loam in equal proportions.
The seeds should be sown at a depth of 1 cm and watered thoroughly. The seedlings should emerge in two to three weeks. Once the seedlings are 10 cm tall, they can be transferred to individual bags or pots with a soil mix of sand, manure, and loam in equal parts.Additionally, the seedlings should be kept in a shaded area with high humidity levels until they achieve a height of 25cm.
Cutting Propagation
Cutting propagation is an alternative method of propagating Grewia arborea. It is usually practised when the seeds are scarce or difficult to obtain. The cuttings should be obtained from branches of a healthy adult plant and should be 15 cm long, 0.5 to 1 cm thick and should contain 3 to 4 leaves.
The cuttings should be suspended in water for four to five days. After that, they should be planted in well-drained soil and watered thoroughly. The cuttings should be kept in a shaded area with high humidity until new growth emerges, then the newly formed leaves indicate success, and the plant can be relocated.
Air Layering
Air layering is another method that is used to propagate Grewia arborea. It is a good method for propagating large-sized clones of the plant. The method involves making a partial cut in the bark of a mature Grewia arborea plant, placing moist soil over that region, and then waiting for roots to emerge. When roots develop, the new plant should be cut from the parent plant and replanted in a suitable location.
The cut should be covered in soil or peat moss and wrapped with plastic to retain moisture. When new growth begins to appear, the rooted branch should be snipped from the parent plant and potted. The rooted cutting should then be placed in a shaded area with high humidity until it is well established.
Disease Management
Grewia arborea is susceptible to various diseases that can cause significant damage if uncontrolled. The following are some common diseases that might affect the plant:
Leaf Spot Disease
One of the most prevalent diseases that affect Grewia arborea is leaf spot disease. It is caused by the fungus Mycosphaerella grewiae. This disease causes the leaves to appear small and yellow with brown spots, which may coalesce and cause distortion of the leaves. The best way to manage this disease involves removing and destroying affected leaves and using fungicides.
Powdery Mildew
Powdery mildew is another common disease that affects Grewia arborea. It is caused by the fungus Oidium grewiae. The disease is characterized by the presence of white, powdery spots on leaves, stems, and flowers of the plant. You can control powdery mildew by reducing humidity around the plant and using chemical fungicides.
Pest Management
Grewia arborea is also susceptible to various pests that can reduce yield and quality. The following are some common pests that might affect the plant:
Mealybugs
Mealybugs are small insects that hide on the underside of leaves or in crevices of the plant. They suck the sap from the plant and cause yellowing and wilting of leaves. You can manage mealybugs by using insecticides or by wiping affected parts of the plants with a cotton swab soaked in rubbing alcohol.
Thrips
Thrips are insects that are barely visible with the naked eye. They cause damage to the plant by sucking sap, which leads to the leaves' scarring and distortion. Thrips can be managed using insecticides or biological controls.
Caterpillars
Caterpillars are the larval stage of butterflies and moths and can cause significant damage to Grewia arborea. They eat the leaves, reducing the plant's ability to photosynthesize and produce food. You can control caterpillars by using handpicking or using insecticides. However, ensure that the method used is selective enough not to harm other beneficial insects such as honeybees.
