Origin
Lobelia giberroa Hemsl. var. volkensii (Engl.) Hauman is a herbaceous perennial plant that originates from East Africa, specifically from Kenya and Tanzania. It thrives in the highlands, at altitudes ranging from 1700-2400m above sea level.
Common Names
This species of Lobelia has several common names, including African lobelia, Volkens’s lobelia, and mountain lobelia.
Uses
The Lobelia giberroa Hemsl. var. volkensii (Engl.) Hauman plant has several medicinal uses. In traditional African medicine, the roots and leaves are used to treat a range of ailments, including malaria, respiratory disorders, and pneumonia. Additionally, it is used to treat sore throats, wounds, and fever.
Aside from its medicinal properties, the plant has ornamental uses. It is often grown as an ornamental plant because of its beautiful blooms that come in shades of blue, purple, and white. They are used to add color to gardens and landscapes. The plant also attracts bees and butterflies, making it a desirable addition to any garden for pollinating insects.
General Appearance
The Lobelia giberroa Hemsl. var. volkensii (Engl.) Hauman plant grows up to 2 meters in height and has a spread of about 1 meter. It has long, lance-shaped leaves that grow to about 10-15cm in length and are arranged in a rosette at the base of the plant. The flowers are typically blue or purple, but can also be white. They are tubular in shape and grow in clusters at the top of the plant. The flowers bloom in the summer, adding a splash of color to the surrounding landscape.
Light Requirements
The Lobelia giberroa Hemsl. var. volkensii (Engl.) Hauman requires full sun exposure for healthy growth and blooming. Insufficient sunlight can cause stunted growth and poor flowering. Therefore, growers should select a location that receives direct sunlight for at least six hours every day.
Soil Requirements
The plant thrives in well-drained soils that are rich in humus and nutrients. It prefers loamy soils that can retain some moisture but do not become waterlogged. The ideal pH range is between 5.5 and 7.5. Gardeners should avoid planting Lobelia giberroa Hemsl. var. volkensii (Engl.) Hauman in heavy clay soils that are prone to waterlogging as it can cause root rot.
Temperature Requirements
The plant grows well in temperate climates with an average temperature range of 15°C to 25°C. It is sensitive to frost and cannot tolerate temperatures below 5°C. Therefore, it is recommended to grow Lobelia giberroa Hemsl. var. volkensii (Engl.) Hauman in spring and summer when the temperatures are favorable. Protecting the plant from cold or hot winds is also important to prevent damage.
Cultivation Methods
Lobelia giberroa Hemsl. var. volkensii (Engl.) Hauman, commonly known as African blue lobelia, requires well-draining soil with a pH range of 5.5 to 6.5. The plant prefers full sun to partial shade and should be sheltered from strong winds. It is recommended to grow the plant from seedlings instead of seeds for better establishment of strong roots. The plant can be propagated through division during spring or fall, with each divided section replanted into a well-prepared planting hole.
Watering Needs
African blue lobelia requires regular watering during the growing season, especially during the hot and dry periods. The soil must be kept moderately moist, but not waterlogged, to prevent root rot. Mulching the plant helps to retain soil moisture and regulates soil temperatures.
Fertilization
The plant requires balanced fertilizer with an N-P-K ratio of 10-10-10 or 20-20-20 every four to six weeks during the growing season to encourage healthy growth and flowering. Over-application of fertilizer can result in excessive vegetative growth at the expense of flowering.
Pruning
Pruning African blue lobelia helps to promote bushy growth and increase flowering. The plant can be pinched back regularly, especially when young, to encourage branching. The plant should be deadheaded to remove spent flowers, prevent seed formation, and encourage continuous blooming.
Propagation of Lobelia giberroa Hemsl. var. volkensii (Engl.) Hauman
Lobelia giberroa Hemsl. var. volkensii (Engl.) Hauman can be propagated through different methods, including:
1. Seeds
Propagation by seeds is the most common method. The seeds should be collected when the capsule is partly open. The collected seeds should be dried and stored in a cool, dry place to ensure they remain viable.
Seeds can be sown in a seedbed or containers filled with a well-draining soil mix of peat and sand. The ideal temperature for seed germination is between 20 and 25°C. Seeds should not be covered with soil as they require light to germinate.
After germination, seedlings can be transplanted into individual containers or directly into the field.
2. Stem cuttings
Propagation by stem cuttings is also possible. Cuttings can be taken in the early morning or late afternoon when the plant is not under extreme stress, and avoid taking cuttings during the flowering season.
The cuttings should be 6-8 cm long, with at least three nodes. The leaves on the lower node should be removed, and the cutting should be treated with rooting hormone powder before planting. The cuttings should be inserted into a well-draining potting mix and kept in a humid environment until roots have developed.
3. Division
The plant can also be propagated by division. Divide mature clumps of the plant in early spring or after the flowering season.
The clumps should be carefully dug up and divided into smaller sections with a sharp, clean tool. Each section should have adequate roots and should be transplanted into a well-draining soil mix.
Propagation of Lobelia giberroa Hemsl. var. volkensii (Engl.) Hauman can be a straightforward process with the right knowledge and care.
Disease and Pest Management for Lobelia gibberoa Hemsl. var. volkensii (Engl.) Hauman
Lobelia gibberoa Hemsl. var. volkensii (Engl.) Hauman may be affected by several pests and diseases. Proper management strategies are essential to keep the plant healthy and productive. Here are some common diseases and pests that may attack the plant and suggested ways to manage them.
Common Diseases
Leaf Spot: Leaf spots may occur as small, irregular yellow or brown spots on the older leaves. They tend to spread, resulting in defoliation. To manage this, promptly remove any infected leaves, avoid overhead watering, and apply fungicidal spray containing copper or chlorothalonil.
Root Rot: Root rot disease is usually a result of overwatering, poor drainage, and poorly aerated soil. The disease usually attacks the root system, leading to wilting, yellowing of leaves, and plant death. The management strategy would be to avoid excess watering, ensure proper drainage, and use well-draining soil. Fungicidal drenches containing thiophanate-methyl or imazalil may also be used to control the disease.
Mildew: Mildew is caused by a fungus that results in white powder-like masses on the plant leaves and stems. To manage this, avoid watering your plant late in the day and create good air circulation by spacing plants properly. If the disease persists, apply a fungicide containing myclobutanil or triforine.
Common Pests
Thrips: Thrips are tiny insects that usually feed on the flowers and tender growth. They cause the plant to have a bronzed appearance and to wilt. The management strategy would be to remove any infected plant parts and spray insecticidal soap or neem oil to control the pests.
Aphids: Aphids are small, pear-shaped insects that suck sap from the stems and leaves of the plant. They cause yellowing and distortion of leaves. To manage these, use insecticidal soap, neem oil, or an alcohol spray containing 70 percent isopropyl alcohol.
Spider Mites: Spider mites are tiny arachnids that usually feed on the undersides of leaves, causing yellowing and stippling. To manage them, wash the plant with water to remove the mites, and use a miticide if necessary.
By following these management strategies, you can significantly reduce the impact of common pests and diseases on your Lobelia gibberoa Hemsl. var. volkensii (Engl.) Hauman plant, ensuring its healthy growth and productivity.
