Origin
Lobelia erinus L. var. schrankii (Sweet) E. Wimm. is a flowering plant species that belongs to the Campanulaceae family. It is native to South Africa, where it is commonly found in the Eastern Cape Province, KwaZulu-Natal Province, and Mpumalanga Province.
Common Names
The plant is commonly known as trailing lobelia, edging lobelia, or simply lobelia. It is also referred to as Lobelia erinus 'Sapphire' in the horticultural industry due to its blue flowers.
Uses
Trailing lobelia is primarily grown as an ornamental plant due to its beautiful blue flowers, which bloom from spring to fall. It is often used as a trailing plant in hanging baskets, window boxes, and containers, where the fine, delicate stems and flowers create an attractive cascading effect. The plant is also used as a bedding plant, edging, and ground cover.
In traditional medicine, the plant is used to treat several ailments such as respiratory tract infections, fever, coughs, and asthma. Some studies have shown that lobelia extracts can be useful as a muscle relaxant and anti-inflammatory agent.
General Appearance
Trailing lobelia is a low-growing, herbaceous perennial plant that typically grows up to 20cm tall and spreads up to 30cm wide. The plant has small, oval-shaped, bright green leaves that are up to 2.5cm long and 1cm wide. The flowers are tiny, blue, and star-shaped, with five petals and a white center. The flowers typically grow in clusters along the stems and bloom profusely from spring to fall.
The plant prefers well-drained soils and full sun to partial shade. It is easy to grow and maintain, and it generally requires moderate watering and occasional fertilization.
Light Requirements
Lobelia erinus L. var. schrankii thrives well in full sunlight or partially shaded environments, receiving at least 4-6 hours of direct sunlight per day. Under bright light conditions, the plant exhibits increased flowering, producing more flowers, and having a more vibrant blue or violet color.
Temperature Requirements
The ideal temperatures for the growth of Lobelia erinus L. var. schrankii range from 15°C to 21°C. This plant grows well in a wide range of temperature, but it experiences slow growth under extreme temperatures such as frost or very high temperatures. Extreme temperatures can also lead to stunted growth and cause dropping of flowers.
Soil Requirements
Lobelia erinus L. var. schrankii grows well in well-aerated soils with a pH ranging from 6.0 to 7.0. This plant thrives best in well-drained fertile soils that are rich in organic matter. The soil should have good water retention capacity, and adequate moisture levels are essential to sustain growth. On the other hand, waterlogging can lead to root rot, leading to the death of the plant.
Cultivation Methods
Lobelia erinus L. var. schrankii (Sweet) E.Wimm. is commonly known as trailing lobelia, a low-growing, annual flowering plant that is easy to cultivate. This plant thrives in fertile, well-draining soils that are evenly moist but never waterlogged. It is ideal to grow the plant under bright, partial shade conditions, especially in regions with hot summers. It can also grow well in full sun but requires frequent watering to sustain its moisture needs.
Watering Needs
Watering is crucial in the care of lobelia erinus L. var. schrankii (Sweet) E.Wimm since it prefers moist soil. Ensure that the soil is always moistened by watering occasionally and adequately. Regular watering is essential in the summer months when the weather is exceedingly hot and dry, and the plant requires more moisture. However, do not overwater the plant, since its roots are susceptible to rotting in wet soil, which can cause damage or even death of the plant.
Fertilization
Although Lobelia erinus L. var. schrankii (Sweet) E.Wimm. does not require frequent fertilization, it is necessary to enrich the soil with essential minerals for optimal growth. Apply a well-balanced fertilizer once a month in the growing season to promote healthy foliage and flowering. Make sure to use a fertilizer that is specifically formulated for flowering annuals and follow the package instructions for the application to prevent over-fertilization, which can be harmful to the plant.
Pruning
Pruning lobelia erinus L. var. schrankii (Sweet) E.Wimm. is not mandatory, but it can help to keep the plant looking tidy and boost further growth. Pinch back the tips of the lobelia stems regularly, especially during the growing season, to encourage the growth of more side shoots and flowers. Additionally, remove any wilted or damaged flowers from the plant periodically, as this can help promote new growth and flowering.
Propagation of Lobelia erinus L. var. schrankii (Sweet) E.Wimm.
Lobelia erinus L. var. schrankii (Sweet) E.Wimm. can be propagated through various methods, including seed sowing, division, and cuttings.
Seed Sowing
The easiest and most common method of propagating Lobelia erinus L. var. schrankii (Sweet) E.Wimm. is through seed sowing. The seeds can be sown indoors in late winter or early spring and transplanted outdoors later when the temperature is stable. Alternatively, the seeds can be directly sown outdoors once the weather warms up. The seeds should be sown in a well-draining soil mix and kept moist until germination, which usually occurs within 7 to 14 days.
Division
Lobelia erinus L. var. schrankii (Sweet) E.Wimm. can also be propagated through division. This method involves dividing an established plant into smaller sections that can be replanted. It is recommended to do this during the spring months when the plant is starting to show new growth. The rootball should be carefully dug up and divided into smaller clumps, with each clump having its own set of roots. These clumps can then be replanted in a new location or into containers.
Cuttings
Another propagation method for Lobelia erinus L. var. schrankii (Sweet) E.Wimm. is through cuttings. This method involves taking stem cuttings from an established plant and rooting them in a well-draining soil mix. The best time to take cuttings is in late spring or early summer when the plant is actively growing. Cuttings should have at least two sets of leaves and be approximately 4 inches long. The bottom set of leaves should be removed, and the cutting should be dipped in rooting hormone before being planted in the soil mix. Cuttings should be kept moist and in a warm, bright location until roots have formed, which usually takes 2 to 3 weeks. The newly rooted plants can then be transplanted into a permanent location or container.
Disease Management
The plant Lobelia erinus L. var. schrankii (Sweet) E.Wimm. is susceptible to various diseases. Here are some common diseases and ways to manage them:
1. Pythium Root Rot
Pythium root rot is a soil-borne fungal disease that thrives in moist soil, causing the roots of the plant to rot. To manage this disease, avoid overwatering the plant and improve the soil drainage. You can also consider using fungicides that contain metalaxyl, mefenoxam, or dimethomorph as active ingredients.
2. Powdery Mildew
Powdery mildew is a fungal disease that appears as a white powdery coating on the leaves, stems, and flowers of the plant. To manage this disease, make sure to space out your plants to increase air circulation, avoid overhead watering, and remove any infected parts of the plant. You can also use fungicides that contain myclobutanil, triforine, or sulfur as the active ingredient.
Pest Management
The plant Lobelia erinus L. var. schrankii (Sweet) E.Wimm. is also prone to attack by several pests. Here are some common pests and ways to manage them:
1. Aphids
Aphids are tiny insects that suck the sap of plants, causing yellowing of leaves and stunted growth. To manage them, you can use insecticides that contain imidacloprid, acetamiprid, or thiamethoxam as the active ingredient. You can also remove them manually by spraying the plant with water or using insecticidal soap.
2. Spider Mites
Spider mites are tiny, eight-legged pests that can cause yellowing and curling of the leaves. To manage them, you can use insecticides that contain abamectin, bifenthrin, or hexythiazox as the active ingredient. You can also wash them off the plant with water or release natural predators like ladybugs and predatory mites.
