Geigeria africana Griess. subsp. ornativa (O.Hoffm.) Merxm.
Geigeria africana Griess. subsp. ornativa (O.Hoffm.) Merxm. is a flowering plant species that belongs to the family Asteraceae. It is commonly known as African hemp, bitter bush, and Sakara. The plant is native to various parts of Africa, including Senegal, Guinea, Sierra Leone, Ghana, Nigeria, and Sudan.
Appearance
The Geigeria africana Griess. subsp. ornativa (O.Hoffm.) Merxm. typically grows as a small shrub or herb that can reach up to 1 meter in height. The leaves are narrow, linear, and pointed, with a dark green color and a tough, leathery texture. The plant produces small yellow flowers that bloom in clusters at the end of the stems.
Uses
The Geigeria africana Griess. subsp. ornativa (O.Hoffm.) Merxm. plant has various medicinal uses, especially in traditional African medicine. The roots, leaves, and stems are used to treat several ailments such as fever, coughs, and menstrual pain. The plant is also used to stimulate milk production in lactating mothers and with its antimicrobial properties, it can be used to treat various infections. In some parts of Africa, the plant is also used as a natural insecticide and pesticide.
The plant contains various phytochemicals such as alkaloids, flavonoids, and tannins that give it its medicinal properties. However, caution should be taken when using the plant, as it can be toxic in high doses.
Light Requirements
Geigeria africana subsp. ornativa requires full sun exposure for optimal growth and flowering. It prefers open areas in the savannah grasslands and can tolerate some shade, but too much shade can lead to poor growth and stunted plants.
Temperature Requirements
Geigeria africana subsp. ornativa is well adapted to hot and dry conditions. It thrives in temperatures ranging from 20°C to 35°C but can withstand temperatures as low as 10°C. During the dry season, the plant goes dormant to conserve energy until the rainy season returns.
Soil Requirements
The plant prefers well-drained soils with moderate to high fertility levels. It can grow in a range of soil types, including sandy loam, clay loam, and rocky soils, as long as they are not waterlogged. The soil pH should be between 6.5 to 7.5 for optimal growth. It is also important to note that Geigeria africana subsp. ornativa is sensitive to soil erosion and should be grown on stable soils.
Cultivation
Geigeria africana Griess. subsp. ornativa (O.Hoffm.) Merxm. is a hardy, perennial plant that can grow in a range of soil types, including sandy or clay soil. It prefers a well-drained soil type but can tolerate slightly moist soil conditions. The plant requires full sun exposure and can grow up to 1.5 meters, forming an erect shrub with woody branches.
The plant is native to Southern Africa and is mainly propagated by seed. It can, however, be propagated using cuttings, but this method is not common. To propagate using seeds, sow them in spring or summer when temperatures are above 20°C. The seeds should be planted about 5 mm deep and covered with a light layer of soil.
Watering needs
The plant is tolerant of drought conditions and can survive long periods without water when it is well established. It is, however, essential to ensure the plant gets enough water during the establishment phase but avoid overwatering, which can cause root rot.
It is recommended that you water the plant between once every week and twice every three weeks, depending on the environmental conditions. It is also advisable to mulch around the base of the plant to reduce water evaporation and weed growth.
Fertilization
The plant does not require frequent fertilization, but it will benefit from a balanced fertilizer once every two to three months. It is essential to follow the manufacturer's recommendations when applying fertilizer, and ensure that the fertilizer is applied around the plant's base and deeply watered afterward.
It is also advisable to add organic matter to the soil once every year to improve soil structure and increase nutrient levels. Organic matter can be added in the form of well-rotted manure or compost.
Pruning
The plant does not require frequent pruning, but it will benefit from light pruning once a year to promote bushier growth and to remove dead or diseased wood. The best time to prune is at the end of the flowering season when the plant is beginning to enter the dormant stage.
When pruning, it is essential to use sterilized pruning tools to prevent the spread of disease. It is also advisable to cut back the branches to about half their size to promote new growth.
Propagation of Geigeria africana Griess. subsp. ornativa (O.Hoffm.) Merxm.
Geigeria africana Griess. subsp. ornativa (O.Hoffm.) Merxm. can be propagated through seeds or cuttings.
Propagation through Seeds
The seeds of Geigeria africana Griess. subsp. ornativa (O.Hoffm.) Merxm. can be sown directly into the soil or in seed trays. The best time to sow seeds is during the rainy season. The soil should be well-drained and fertile. The seeds should be planted at a depth of about 1 cm and covered lightly with soil. Regular watering is necessary until the seedlings are established.
Propagation through Cuttings
The cuttings of Geigeria africana Griess. subsp. ornativa (O.Hoffm.) Merxm. can be taken from the stem tips or lateral shoots. The best time to take cuttings is during the rainy season. The cuttings should be about 10-15 cm long and should have at least 2-3 nodes. The leaves on the lower half of the cutting should be removed, and the cutting should be dipped in rooting hormone. The cutting should be planted in well-drained soil and watered regularly until it is established.
Irrespective of the method used, Geigeria africana Griess. subsp. ornativa (O.Hoffm.) Merxm. can take up to 4-6 weeks for the roots to establish, after which regular watering is essential.
Disease Management
Geigeria africana Griess. subsp. ornativa is susceptible to several diseases, which can affect its overall health and productivity. Here are a few common diseases that might affect the plant, along with ways to manage them:
- Leaf Spot: This disease is characterized by circular or irregular spots on the leaves. It can be caused by various fungi and bacteria. To manage leaf spot, remove infected leaves and avoid wetting the foliage when watering the plant. You can also use fungicides to control the spread of the disease.
- Root Rot: This disease is caused by fungi that attack the roots and can lead to wilting, yellowing, and eventual death of the plant. To manage root rot, ensure proper drainage and avoid overwatering the plant. You can also use fungicides to control the spread of the disease.
- Powdery Mildew: This disease is characterized by a white powdery growth on the leaves, stems, and flowers of the plant. It is caused by various fungi and can lead to stunted growth and reduced yield. To manage powdery mildew, remove infected plant parts and improve air circulation around the plant. You can also use fungicides to control the spread of the disease.
Pest Management
Geigeria africana Griess. subsp. ornativa is also susceptible to various pests, which can damage the plant and reduce its productivity. Here are a few common pests that might affect the plant, along with ways to manage them:
- Aphids: These small insects suck the sap from the leaves and stems of the plant, leading to curling and yellowing of the leaves. To manage aphids, remove them by hand or use insecticidal soap to control their population.
- Spider Mites: These tiny pests feed on the plant sap, causing yellowing and stippling of the leaves. To manage spider mites, improve air circulation around the plant and use insecticidal soap or neem oil to control their population. You can also use predatory mites to feed on spider mites.
By following these disease and pest management strategies, you can keep Geigeria africana Griess. subsp. ornativa healthy and productive throughout its lifespan.
