Overview
Lobelia erlangeriana Engl. is an evergreen flowering plant with beautiful blue flowers that belongs to the Campanulaceae family. It is native to East Africa and was discovered by an Austrian botanist named Franz Siegfried Junghuhn in the late 19th century.Common Names
The plant is commonly known as Erlanger Lobelia or Blue Lobelia, named after its blue-colored flowers. In Tanzania, it is called "Singiliti" by the Swahili speaking people.Appearance
Lobelia erlangeriana grows up to a height of 1.5 meters with a spread of up to 30 centimeters. The plant has woody and bushy stems that are roughly textured with a green color. The leaves are dark green and narrow with a length of 10 - 18 centimeters, and 2 - 6 centimeters wide. It has bright blue flowers that are clustered at the top of the stem creating a spike-like appearance. The flowers are tubular, with five petals that join together and form a split, which is harmoniously symmetrical, measuring up to 2.5 cm in diameter.Uses
Traditionally, Lobelia erlangeriana has been used in the Eastern African region as a medicinal plant to treat various ailments such as coughs, epilepsy, and snakebites. The plant contains lobeline, a compound that acts as a respiratory and circulatory stimulant. Additionally, the plant has potent analgesic properties, which make it effective in pain relief. The plant also contains high levels of folate and iron, which makes it a valuable plant for women in their childbearing years. In horticulture, Lobelia erlangeriana is grown as an ornamental plant in gardens and parks due to its beautiful blue flowers that provide a stunning display. The plant requires moist and well-drained soil and thrives in full sunlight.Light Requirements
Lobelia erlangeriana Engl. is a plant that prefers to grow in partial shade to full sun conditions. Exposure to direct sunlight for extended periods may be too intense for this species, leading to damage and death. On the other hand, insufficient light may result in reduced vigor and poor flowering. Therefore, ensuring that this plant gets an adequate amount of light is crucial for optimal growth.
Temperature Requirements
As a tropical plant, Lobelia erlangeriana Engl. thrives best in warm conditions. The ideal temperature range for this species is between 15°C to 30°C. Temperatures below 10°C may cause the plant to enter dormancy or die. Lobelia erlangeriana Engl. is not tolerant of frost and should be protected in winter months in cold regions.
Soil Requirements
The soil type and quality can significantly impact the growth and development of Lobelia erlangeriana Engl. This plant prefers a well-draining, humus-rich, and slightly acidic soil with a pH of around 6.0 to 7.0. The ideal soil should be loose, airy and capable of retaining moisture while avoiding waterlogging. Soil fertility is essential, and it is advisable to enrich the planting site with organic matter or loamy soil mix. Proper soil preparation will ensure that the plant has adequate nutrients and suitable growing conditions.
Cultivation Methods
Lobelia erlangeriana Engl., also known as Erlanger's lobelia, is a herbaceous perennial plant native to Africa. It thrives best in a partially-shaded area with well-draining soil, and can grow up to 2 meters tall if not pruned back. When planting, ensure that the roots are covered but the crown is exposed to prevent rotting. The plant spreads through underground rhizomes, so provide enough space for it to grow.
Watering Needs
Water the plant frequently during the growing season, especially during prolonged dry spells. Make sure to water at the base of the plant to keep the foliage dry and prevent fungal diseases. Overwatering can lead to root rot, so ensure that the soil is well-draining and never soggy. Reduce watering in the dormant season to prevent waterlogging the roots.
Fertilization
Feed the plant with a balanced fertilizer in the spring to promote healthy growth. Avoid overfeeding as this can lead to lush foliage but fewer blooms. Top-dress with compost in the fall to improve soil nutrients and prepare for the next growing season.
Pruning
Pruning is essential to maintain the plant's shape and encourage bushier growth. Cut back the stems by a third in mid-summer to promote a second flush of blooms. Deadhead regularly by removing spent flowerheads to encourage more blooms and prevent self-seeding. Cut back to the ground in late fall after the foliage has died back to prepare for the dormant season.
Propagation of Lobelia erlangeriana Engl.
Lobelia erlangeriana Engl., commonly known as Erlanger's Lobelia, is propagated by seeds and cuttings. The following are the propagation methods:
Propagation by Seeds:
The most common, and recommended, method of propagating Lobelia erlangeriana is through seeds. Following are the steps to grow the plant from seeds:
- Collect the seeds from a healthy plant during its growing season.
- Clean the seeds and soak them in water for at least 12-24 hours before planting.
- Plant the seeds in well-draining potting soil, and make sure they are not buried too deeply.
- Place the pot in a warm, moist area with indirect sunlight.
- Keep the soil consistently moist but not waterlogged. Germination should take between 14-21 days.
- Once the seedlings have grown at least 2-3 sets of leaves, they can be transplanted to their permanent location.
Propagation by Cuttings:
Propagation by cuttings is another method of propagating Lobelia erlangeriana; however, it is not as common as propagation by seeds. Here are the steps to propagate the plant through cuttings:
- Select a healthy plant with strong stems and no signs of disease or pests.
- Take cuttings that are about 5-6 inches long, and make a clean cut just below a node.
- Remove the leaves from the bottom 2 inches of the cutting.
- Dip the cut end of the stem in rooting hormone.
- Insert the cutting into well-draining, moist potting soil.
- Place the pot in a warm, humid area with indirect sunlight.
- Keep the soil consistently moist but not waterlogged.
- The new plant should be established in a few weeks, and can be transplanted to its permanent location.
Propagation of Lobelia erlangeriana is not difficult and can be done with either seeds or cuttings. It is important to start with a healthy plant, and to provide the plants with proper care and attention throughout the propagation process.
Disease and Pest Management for Lobelia erlangeriana Engl.
Lobelia erlangeriana Engl. is a beautiful plant known for its vibrant blue flowers and green foliage. However, like all other plants, it is susceptible to certain diseases and pests. Here is some information on the most common diseases and pests that affect Lobelia erlangeriana and ways to manage them.
Common Diseases
Crown Rot: Crown rot is a fungal disease that affects the roots and crown of the plant. It is usually caused by poor soil drainage. To manage crown rot, improve the soil drainage and avoid overwatering. Remove and destroy any infected plants.
Leaf Spot: Leaf spot is a fungal disease that appears as small, round spots on the leaves. To manage this disease, remove any infected leaves and avoid overhead watering. Use a fungicide as a preventative measure.
Powdery Mildew: Powdery mildew is a fungal disease that appears as a white powdery coating on the leaves and stems. To manage this disease, improve the air circulation around the plant and avoid overhead watering. Use a fungicide to reduce the spread of the disease.
Common Pests
Aphids: Aphids are small, soft-bodied insects that suck the sap from the leaves and stems of plants, causing stunted growth and yellowing of the leaves. To manage them, wash the plant with a strong spray of water or use an insecticidal soap.
Thrips: Thrips are tiny, slender insects that feed on the leaves and flowers of plants and can cause distortion and discoloration of the plant. To manage them, use yellow sticky traps or insecticidal soap. Prune and destroy any heavily infested plant parts.
Spider Mites: Spider mites are tiny, eight-legged insects that feed on the undersides of the leaves of the plant, causing yellowing and wilting. To manage them, remove and destroy any heavily infested leaves and use a miticide.
Regular inspection and good cultural practices such as proper watering and fertilization can help reduce the incidence of diseases and pests on Lobelia erlangeriana. If the problem persists despite your best efforts, consult a professional gardener or a plant specialist.
