General Description
Grewia obovata K.Schum. is a small deciduous tree or large shrub that belongs to the family Malvaceae. It can grow up to a height of 8 meters tall, and can be found in a range of habitats including woodlands, grasslands, and savannas. This plant is commonly known as the Waterberry or Lavender star, and is native to various countries in Africa such as Zimbabwe, Zambia, and Mozambique.
Appearance
The Waterberry is characterized by its broadly obovate leaves that measure approximately 5-10 cm long and 2-6 cm wide. Its leaves are dark green with a glossy surface that is serrated at the edges. The tree produces small white to pale pink flowers that bloom in the summer, followed by a small greenish fruit similar in size to a cherry. The fruit ripens to purple or black and is edible, with a slightly acid flavor.
Uses
Grewia obovata K.Schum. has various uses across Africa. The tree’s bark can be used as a traditional medicine for treating various ailments such as diarrhea, stomach ache, and fever. The fruit is rich in vitamins, and is consumed both raw and cooked in pies, jellies, and jams. The tree is also used for its timber, which is durable and hardy. The wood is used for making furniture, utensils, and tools.
Growth Conditions for Grewia obovata K.Schum.
Grewia obovata K.Schum., commonly known as the cross-berry tree, is a small to medium-sized tree that is native to southern Africa. In order to thrive, it requires specific growth conditions in terms of light, temperature, and soil.
Light Requirements
As a tree species native to southern African savannas and woodlands, Grewia obovata K.Schum. thrives in full to partial sunlight. In nature, it is often found growing on savanna edges and open woodlands, where it is exposed to high levels of sunlight throughout the day. In cultivation, it should be placed in a location where it can receive at least 6 hours of direct sunlight each day for optimal growth.
Temperature Requirements
Grewia obovata K.Schum. grows best in warm temperatures, typical of southern Africa. It is adapted to withstand prolonged periods of heat and drought, as well as occasional frost. In cultivation, it can tolerate temperatures as low as -1 degree Celsius, but it does best in temperatures between 18-30 degrees Celsius.
Soil Requirements
Grewia obovata K.Schum. is an adaptable species that can grow in a range of soil types, from sandy to loamy soils. However, for optimal growth, it requires well-draining soils that are rich in nutrients. In nature, it is typically found growing in soil that is neutral to slightly acidic in pH. To promote healthy growth in cultivation, it is best to plant this species in soil that has been amended with organic matter and has good drainage. Additionally, the tree is able to tolerate drought, making it ideal for growth in areas with limited water.
Cultivation methods
Grewia obovata K.Schum. is a shrub that thrives well in subtropical and tropical climates and requires impressive management to achieve its maximum potential. Ensure to cultivate it in well-drained soils with ample nutrients. The recommended planting season is the onset of the rainy season in the tropics and early spring in subtropical zones. Propagation can be done by seed or cuttings, but it is easier using cuttings.
Watering Needs
As with many plants, Grewia obovata K.Schum. requires sufficient water to grow. These plants must have access to well-drained soil that can hold water and air as they dislike extended waterlogging. During the dry seasons, ensure to water regularly to keep the soil moist. Watering daily or every two days is advisable, depending on the weather conditions. Adequate moisture levels can help the plant resist pests and diseases.
Fertilization
To ensure Grewia obovata K.Schum. thrives, you need to fertilize it. This shrub requires fertilization every few months, mainly organic fertilizers. Manure, bone meal, and blood should be used sparingly and only applied once you have prepared and tilled the ground. A balanced application of NPK fertilizer ensures that nutrients obtain the proper ratios for your shrub to thrive. Avoid applying fertilizers during the dry season, as it can burn the roots.
Pruning
Pruning helps to stimulate growth and prevent overcrowding. With Grewia obovata K.Schum., pruning should begin when it is young and continue every year. Correct pruning helps to retain the shrub's shape and encourages it to produce more flowers and fruits. Prune during the dry season, as it helps to limit the spread of diseases like anthracnose. Remove diseased, weak, or dead branches as soon as possible and avoid pruning when the shrub is flowering.
Propagation of Grewia obovata K.Schum.
Grewia obovata K.Schum., commonly known as Grey-leaved grewia, is a deciduous shrub or small tree that belongs to the family Malvaceae. This native of Africa can propagate through several methods that include:
Seed Propagation
Grewia obovata K.Schum. can be propagated through seeds, which are easy to obtain from mature fruits. The seeds need to be scarified or nicked on the surface before sowing, to enhance germination. Sowing should be done in a well-draining soil mixture, in a nursery bed or in pots. The seeds are covered lightly with soil, then watered and kept in a shaded area. Germination should start after 2-3 weeks, and the seedlings can be transplanted in larger containers or directly to the field when they are 4-6 inches tall and have several leaves.
Cutting Propagation
Propagation of Grewia obovata K.Schum. through cuttings is an effective method that produces identical plants to the parent plant. Semi-hardwood cuttings can be collected from the parent tree during the active growing season. The cuttings should have a length of 8-12 inches and be at least 1/4 inch in diameter. The bottom leaves should be removed, and the cuttings dipped in a rooting hormone powder to increase the chances of success. The cuttings are then planted in a rooting medium, such as perlite, vermiculite, or coarse sand, then covered with a plastic bag or dome to maintain humidity. The cuttings should be kept in a shaded area with temperatures of 70-75°F (21-24°C). Rooting should occur after 3-4 weeks, and the rooted cuttings can be transplanted in larger containers or directly to the field after 2-3 months.
Suckers Propagation
Grewia obovata K.Schum. can also propagate through suckers, which are new shoots that emerge from the base of the parent plant. Suckers can be separated from the parent plant using a sharp knife or a spade, making sure to remove some of the roots too. The suckers are then planted in a well-prepared field or in a container, taking care to keep the soil moist and to protect them from direct sunlight. The suckers should establish well within a few weeks, and the resulting plants will have the same genetic makeup as the parent plant.
Disease and Pest Management for Grewia obovata K.Schum.
Grewia obovata K.Schum. is a plant that belongs to the family Malvaceae and is commonly found in the tropical regions of Africa. Despite being known for its hardiness, the plant is also susceptible to certain diseases and pests, which can lead to stunted growth and reduced yield. Therefore, it is essential to identify common pests and diseases and employ preventive measures for effective disease and pest management.
Disease Management
1. Anthracnose: This fungal disease causes the leaves of the plant to wilt and turn brown. It also causes sunken spots on the stems and fruits. The disease spreads easily during wet weather conditions. To manage the disease, it is important to remove infected plant parts, improve air circulation, and avoid overhead watering. Fungicides sprays such as copper-based fungicides are also effective against anthracnose.
2. Leaf spot: Leaf spot is a fungal disease that causes yellow or brown spots on the leaves of the plant. The spots may merge, leading to defoliation. The disease can be controlled by removing infected plant parts and improving air circulation. Copper-based fungicides are also effective against leaf spot.
Pest Management
1. Whiteflies: Whiteflies are small, winged insects that suck the sap from the leaves of Grewia obovata K.Schum. The infested plants have a stunted growth, yellowing of leaves, and the leaves may also drop prematurely. The pests can be managed by spraying insecticidal soap, horticultural oil, or neem oil. Sticky traps and reflective mulch are also effective in controlling whiteflies.
2. Mealybugs: Mealybugs are pests that cause the leaves to wilt and turn yellow. They suck the sap of the plant and excrete a sticky substance called honeydew, which attracts ants. To control the pest, it is essential to remove the infected plant parts and spray insecticidal soap or oil. Beneficial insects such as ladybugs and lacewings can also be introduced as they feed on mealybugs.
In conclusion, timely identification and management of pests and diseases are crucial to maintain the health of Grewia obovata K.Schum. plant. Regular monitoring, sanitation practices, and use of organic methods can prevent the pests and diseases from damaging the plant.
