Overview
Grewia gossweileri (Burret) Exell, commonly known as the Namibia raisin, is a small shrub or tree that belongs to the Malvaceae family. The plant is native to Namibia and widely distributed in other African countries, including Angola, Botswana, Malawi, Mozambique, South Africa, Zambia, and Zimbabwe.Description
Grewia gossweileri can reach a height of 4 to 6 meters and has a rounded or spreading crown with a single stem or multiple stems arising from the base. The bark is dark grey and rough, with characteristic longitudinal fissures. The leaves are alternate, simple, and ovate, with a length of 2 to 6 cm and a width of 1 to 5 cm. They are dark green on the upper surface and pale green on the lower surface, with serrate margins and a rounded apex. The flowers are small, white, and occur in clusters of 1 to 4 at the base of the leaves. The fruits are fleshy berries, yellow to orange when ripe, and edible.Uses
Grewia gossweileri is an important medicinal plant widely used in traditional medicine to treat various ailments. The bark, leaves, and roots are used to treat diarrhea, dysentery, fever, hypertension, tuberculosis, and wounds. The bark is also used as a fish poison and to make ropes. The fruits are consumed fresh or dried and are used to make juice, jam, and wine. They are also used as a natural sweetener and a source of vitamins and minerals.Conservation
Grewia gossweileri is not listed as a threatened species, but it is under pressure due to deforestation, overgrazing, and unsustainable harvesting of bark and fruits. There is a need for conservation strategies that promote sustainable harvesting and cultivation of the plant to ensure its availability for future generations.Light Requirements:
Grewia gossweileri generally prefers full sunlight for optimal growth and development. It is a sun-loving plant that requires bright and direct light to thrive. Lack of adequate sunlight can lead to stunted growth and poor yield.
Temperature Requirements:
Grewia gossweileri is a tropical plant and grows well in warm climatic conditions. The temperature range for optimal growth is between 20°C to 35°C. Temperatures below 15°C can lead to poor growth and yield. In cooler climates, the plant can be grown in a greenhouse to provide the necessary warmth and protection.
Soil Requirements:
The plant prefers well-drained soils that are fertile, rich in organic matter, and slightly acidic. A pH range of 5.5 to 6.5 is optimal for the growth and development of Grewia gossweileri. The soil should be deep enough to allow for proper root development and moisture absorption. Adding compost or well-rotted manure can help improve the soil quality.
Water Requirements:
Grewia gossweileri requires moderate watering. The plant should be watered regularly, especially during the growing season, to keep the soil moist but not waterlogged. Overwatering can lead to root rot, while under watering can cause drought stress and poor yield.
Fertilizer Requirements:
The plant benefits from regular fertilization to meet its nutrient requirements and promote healthy growth. Apply a balanced fertilizer containing nitrogen, phosphorus, and potassium every four to six weeks during the growing season. Over-fertilization can lead to excessive vegetative growth and reduced yields.
Cultivation Methods
Grewia gossweileri is a fast-growing and hardy plant that thrives in tropical and subtropical regions. It favors well-drained soils with a pH range of 5.0-7.5 and prefers partial shade to full sun. The plant is propagated by seed or cuttings and should be transplanted into the field under optimal conditions.
Watering Needs
The plant requires moderate watering during the dry season. Watering should be done every three days and increased gradually as the plant matures. Overwatering should be avoided as this can lead to root rot and other plant diseases.
Fertilization
Fertilizers should be applied during the planting period. This should be followed by additional fertilizing at the onset of the rainy season. Organic matter or compost is recommended as they improve soil fertility and increase the plant's resistance to pests and diseases. Synthetic fertilizers should be used sparingly as they can lead to soil degradation and environmental pollution.
Pruning
Regular pruning is necessary to maintain the plant's shape and promote healthy growth. Pruning should be carried out during the dormant season, typically after the fruiting period. Dead and diseased branches should be removed, and unwanted shoots should be trimmed back to encourage bushy growth. It is vital to sterilize pruning equipment before use to prevent the spread of diseases.
Propagation of Grewia Gossweileri
Grewia gossweileri, commonly known as Crossberry, is a fruit-bearing shrub that belongs to the Malvaceae family. The plant is mainly found in Southern Africa, particularly in Angola, Namibia, and Zambia. It has gained popularity in recent years due to its nutritional value, making it a great prospect for commercial cultivation. Propagation of the plant is traditionally through seeds, suckers, and cuttings.
Propagation by Seed
Propagation of Grewia gossweileri through seed is the most common method as the plant produces a considerable quantity of seeds every season. Seeds can be collected from the ripe fruit and should be dried under the sun before planting. After drying, the seeds can then be scarified for a better germination rate. This method is preferred as it results in plants that exhibit good rootstock vigor and, in return, have high fruit yields.
Propagation by Cuttings
Propagation by cuttings is another method that can be used for Grewia gossweileri. The method involves taking a mature stem about 15cm in length and planting it under controlled conditions such as a greenhouse. Successful rooting requires adequate humidity and moisture in the soil. Although this method has been successful in propagating the Crossberry plant, it results in a weaker rootstock, thus reduced productivity.
Propagation by Suckers
Natural regeneration of Grewia gossweileri occurs through the formation of suckers that sprout from the roots of established plants. These suckers can be carefully pruned and transplanted into other sites. This method has been successful in propagating the desired traits of the plant, resulting in high fruit yields due to the vigor of the rootstock.
Disease and Pest Management for Grewia gossweileri (Burret) Exell
Grewia gossweileri (Burret) Exell, commonly known as Hardy grewia, is a hardy plant that grows well in many environments. However, like all plants, it can be affected by diseases and pests. Here are some of the common diseases and pests that affect the plant, along with ways to manage them effectively:
Diseases
1. Leaf spot - This is a fungal disease that causes circular patches with brown or yellow centers to appear on the leaves. To manage this disease, remove the infected leaves and dispose of them properly. Also, avoid watering the plant from overhead as the disease spreads through moisture. Instead, water the plant from the base.
2. Powdery mildew - This is a fungal disease that is characterized by a white powdery substance on the leaves. It can weaken the plant and cause it to lose vigour. To manage this disease, prune away any infected areas, and improve air circulation around the plant. In severe cases, use a fungicidal spray.
3. Root rot - This is a disease caused by the fungus Phythophthora sp. that causes the roots to rot and the plant to wilt. To manage this disease, avoid overwatering the plant and make sure it has good drainage. Additionally, you can use a fungicide to treat the soil and prevent the spread of the disease.
Pests
1. Spider mites - These are tiny pests that are difficult to see with the naked eye. They cause damage to the leaves, causing them to turn yellow and fall off the plant. To manage them, spray the plant with water daily to wash them away, and use insecticidal soap or neem oil to control them.
2. Whiteflies - These are tiny insects that suck the sap from the leaves of the plant. They are often found on the undersides of leaves. To manage them, use yellow sticky traps to catch them, and use insecticidal soap or neem oil to control them.
3. Scale insects - These are small, immobile insects that attach themselves to the leaves and stems of the plant. They suck the sap from the plant and can cause significant damage. To manage them, use a soft brush to dislodge them from the plant, and use insecticidal soap or neem oil to control them.
By following these tips, you can help keep your Grewia gossweileri (Burret) Exell plant healthy and productive. Remember to always follow the instructions on any chemicals used and to wear the appropriate protective gear when applying.
