Lobelia Erinus L. Var. Grandiflora Paxton

Overview

Lobelia erinus L. var. grandiflora Paxton, also known as Large-Flowered Lobelia, is a species of flowering plant in the Campanulaceae family. It is native to southern Africa and is widely cultivated as an ornamental plant for its beautiful blue, violet, pink, or white flowers that bloom in the spring and summer.

Appearance

The Large-Flowered Lobelia grows as an annual or perennial herb and can reach a height of up to 15 cm. Its stems are slender and erect, and its leaves are ovate, toothed at the margins, and alternately arranged. The flowers are trumpet-shaped, about 2.5 cm long, and have five petals fused into a lower tube, with the tips flaring out. They grow on terminal spikes and are often visited by bees and butterflies.

Common Names

The Large-Flowered Lobelia is known by several common names, including Cape Lobelia, Edging Lobelia, Garden Lobelia, and Trailing Lobelia. In Afrikaans, it is called bloutrompetjie, which translates to "little blue trumpet."

Uses

The Large-Flowered Lobelia is primarily grown as an ornamental plant in gardens, borders, and containers. It prefers full sun to partial shade and well-drained soil. It is also used in traditional African medicine to treat respiratory problems, rheumatism, and muscle pain. The plant contains alkaloids, flavonoids, and saponins, which have been shown to possess anti-inflammatory, analgesic, and antispasmodic properties.

Light Requirements

Lobelia erinus L. var. grandiflora Paxton grows best in full sun to partial shade. However, if you are growing it in an area where the summers are hot, it is better to provide some shade to prevent the plant from getting stressed.

Temperature Requirements

The ideal temperature for growing Lobelia erinus L. var. grandiflora Paxton is between 15°C to 25°C. It can tolerate temperatures as low as -2°C and as high as 35°C. However, if the temperature rises above 30°C, you need to provide some shade to the plant to protect it from heat stress.

Soil Requirements

Lobelia erinus L. var. grandiflora Paxton prefers well-drained soil that has a pH range of 5.5 to 6.5. It can grow in a wide range of soils, including loamy, sandy, and clay. However, the soil should be fertile and rich in organic matter to support the growth of the plant.

Cultivation

Lobelia erinus L. var. grandiflora Paxton, commonly known as the edging Lobelia, is a popular flowering plant that can be cultivated with ease. The plant prefers cool temperatures and partial shade but can also grow well in full sun with proper watering and care. The best time to plant the lobelia is in early spring when the soil is moist and has a temperature of about 60° F.

Before planting, ensure that the soil is well-draining and rich in organic matter. You can cultivate the lobelia in pots or garden beds, provided the planting site is not waterlogged. Space the plants 6-8 inches apart to allow for maximum air circulation that helps prevent disease and promotes healthy growth.

Watering needs

Lobelia erinus L. var. grandiflora Paxton requires consistent watering to thrive and produce healthy blooms. The plant prefers moist soil, and you should water it at least once a week or more frequently during hot summer days. When watering, avoid splashing the leaves to prevent fungal growth, which can lead to leaf drop or plant death.

It is also recommended to mulch around the plant to help retain moisture in the soil and prevent water loss through evaporation. Always ensure that the soil is not waterlogged as it can cause the roots to rot.

Fertilization

Adding the correct nutrients to the soil will help the lobelia erinus L. var. grandiflora Paxton grow healthy and produce plenty of blooms. Fertilize the plant with a balanced fertilizer, such as 10-10-10, once a month during the growing season from spring to fall. Follow the manufacturer's instructions for the correct application rates, as overfertilization can harm the plant.

Pruning

Pruning lobelia erinus L. var. grandiflora Paxton helps to stimulate healthy growth and keep the plant looking neat. Use sharp, sterilized pruning shears to cut back any dead or yellowing leaves or stems. Remove spent flowers to encourage new blooms and prevent seed production. You can also pinch back the stems to promote bushy growth, ensuring that you leave some leaves on the shortened stems to allow for photosynthesis.

Propagation of Lobelia erinus L. var. grandiflora Paxton

Lobelia erinus L. var. grandiflora Paxton, commonly called edging lobelia, is a popular trailing annual flowering plant. It is often used to add color to the garden edges, hanging baskets, and containers. The following are the propagation methods of Lobelia erinus L. var. grandiflora Paxton.

Seed Propagation

One of the easiest ways to propagate Lobelia erinus L. var. grandiflora Paxton is through seed. The seeds can be sown directly in the garden or indoors. Here are the steps to follow:

1. Start by purchasing quality seeds from a reputable source.
2. Sow the seeds indoors in early spring, 6 to 10 weeks before the last frost date in your area.
3. Use a well-draining soilless mix to fill your seed tray and water gently.
4. Scatter the seeds on top of the soil, making sure they are in contact with the surface.
5. Cover the tray with plastic wrap to keep the soil moist and warm.
6. Once the seedlings emerge, remove the plastic wrap and move the tray to a sunny, warm location.
7. Transplant the seedlings into the garden or containers once they have grown a few sets of true leaves and the outside temperatures are warm enough.

Cuttings Propagation

Another way to propagate Lobelia erinus L. var. grandiflora Paxton is through stem cuttings. Here are the steps to follow:

1. Choose a healthy, non-flowering stem from the parent plant.
2. Cut a 4 to 6 inches section below a node, using a sharp and clean pair of scissors.
3. Remove the leaves from the bottom half of the stem.
4. Dip the cut end of the stem into rooting hormone powder.
5. Plant the stem into a well-draining potting mix.
6. Water the cutting and cover it with a plastic bag to keep the humidity levels high.
7. Place the pot in a warm area with bright, indirect light.
8. Once the roots have formed, remove the plastic bag and transplant the cutting into a larger container or directly into the garden.

Disease Management

Lobelia erinus L. var. grandiflora Paxton is susceptible to a number of diseases that can affect its growth, development, and productivity. Some of the common diseases that may affect this plant include:

• Pythium root rot
• Botrytis blight
• Mildew
• Leaf spot

One effective way to manage these diseases is to maintain good cultural practices, such as proper watering, fertilization, and pruning. It is also recommended to apply preventive fungicide treatments to help prevent and manage these diseases. In addition, removing diseased plant material and debris from the growing area can also help prevent the spread of disease.

Pest Management

Lobelia erinus L. var. grandiflora Paxton is also vulnerable to pest attacks that can cause damage to the plant. Some of the common pests that may affect this plant include:

• Aphids
• Spider mites
• Whiteflies
• Caterpillars

To manage these pests, it is recommended to regularly inspect the plants and remove any pests that are detected. Insects can be controlled using natural predators or insecticides. Applying insecticidal soaps and oils may also help to manage pests. It is important to follow label instructions when using any pesticide product, and to avoid overuse or misuse of these products that may harm beneficial insects or pollinators.