Lobelia care

The Lobelia flower (Lobelia erinus) blooms from spring to autumn and requires plenty of water during this time. It has high light requirements, but it doesn't like direct sunlight and high heat. The planting of seedlings is due around April.

This species, originally from South Africa, is a perennial where it can be overwintered frost-free; otherwise, it is grown as an annual. There are spherical or cushion-forming varieties, but the most striking is the trailing blue lobelia, which catches the eye whether planted in a balcony box or hanging basket.

Lobelia flower (Lobelia erinus), named after the Flemish botanist Matthias de L'Obel, is particularly popular among plant lovers, thanks to its stunning, colorful flowers.

The blue Lobelia, which comes in trailing, upright, and dwarf varieties, doesn't grow very tall. Its height does not exceed 10 inches (25 cm). Despite its small size, it can be a beautiful decoration for any balcony, thanks to its delicate, small flowers that bloom from May to October.

Its tiny flowers start blooming from the second half of May and continue until October or the first frost. Today, white and pink varieties are also available, but the blue lobelia remains the most common. Lobelia can be planted not only in the garden but also on balconies. Whether in a balcony box or a larger container, it will be a striking splash of color.

In the garden, it is an excellent choice as ground cover or border plant in sunny areas. It looks great with other low-growing garden flowers, such as dwarf marigold, sweet alyssum, or petunia.

Lobelia is a densely branching, low-growing, herbaceous ornamental plant. The dwarf Lobelia grows only 4 - 6 inches (10 - 15 cm) tall, while the trailing Lobelia cascades down like a waterfall. The flowers barely exceed 0.4 inches (1 cm), but they bloom in such abundance at the stem tips and leaf axils that they cover the light green foliage. Another advantage is that its requirements are modest.

Lobelia Flower Varieties

There are several Lobelia varieties, and their care is similar for all types. The most well-known lobelia varieties are:

• Dwarf Lobelia - Lobelia erinus
• Trailing Lobelia - Lobelia erinus pendula
• Cardinal Flower - Lobelia cardinalis
• Showy Lobelia - Lobelia speciosa
• Indian Tobacco - Lobelia siphilitica

Lobelia Care

Light Requirements

Generally, Lobelia prefers bright, sunny, and partially shaded locations. This depends on the temperature and the intensity of the sun. However, it is important for the lobelia to receive plenty of sunlight to bloom.

In hot temperatures and intense sunlight, place it in a bright but partially shaded location. Ideally, it should receive direct sunlight in the morning and evening hours but be shaded during the midday and afternoon hours.

At lower temperatures (~80 °F / 27 °C), it can be placed in direct sunlight.

When kept indoors, a north or west-facing window is ideal for lobelia, where it gets enough light but is not exposed to intense direct sunlight.

Temperature Requirements

Lobelia thrives in moderate temperatures, ranging from 64 - 77 °F (18 - 25 °C). Temperatures above 80 °F (27 °C) are considered high for it. In such cases, it is advisable to provide shade to prevent the plant from overheating. Excessive heat can slow down its growth and reduce blooming.

If not planted in the garden, choose a light-colored pot or container, as dark containers absorb the sun’s heat, increasing the temperature of the soil and, in turn, the entire plant.

Watering Requirements

It requires regular watering, especially during drier periods. Ideally, the soil of Lobelia should always be moist but not waterlogged. Avoid letting the soil dry out completely between waterings. Water at the base of the plant or from below to prevent water from getting on the leaves.

If Lobelia is in a pot or container, ensure it has drainage holes to allow excess water to escape.

Lobelia can tolerate short periods of drought, but the shoot tips will wilt. After a thorough watering, the plant will revive. Cut back the wilted parts!

Planting

Planting Lobelia is typically done in spring, after the last frost. Use well-draining soil. The soil can be loosened with compost and manure, which also improve its nutrient content.

When planting Lobelia seedlings, leave a spacing of 4 - 8 inches (10 - 20 cm) between them to give them enough space to grow and bush out. If planting in a container or hanging basket, ensure there is enough space for the bushy plant to spread in all directions.

When planting, dig a hole slightly larger than the root ball. Place the plant in the hole and cover it with soil up to the same level as it was in the nursery pot. Fill the hole with soil and gently press down around the base of the plant.

Fertilization

Fertilizing Lobelia is not strictly necessary, but it can promote more abundant flowering. Do not overdo it, as excessive fertilization may result in lush foliage growth rather than blooming.

Overwintering

Lobelia can be overwintered indoors as it is frost-sensitive. For this reason, many people treat it as an annual and replant it in spring. If overwintering, bring it indoors before the first frost if it was kept outdoors. Place it in a cool but bright location, as it needs plenty of light during the winter.

Before overwintering, prune it to a compact size and remove elongated or tangled shoots.

Reduce watering during the winter months, as less sunlight and lower temperatures slow down its growth.

During winter, Lobelia may enter a dormant state, with slowed growth or even complete stagnation. It is normal if it sheds some leaves and produces fewer flowers during this period.

Additional Care

The basic care for Lobelia involves planting the seedlings in nutrient-rich soil in spring and watering regularly. After the peak flowering period in July, cutting the plant back to two-thirds of its height will encourage new shoots, allowing it to bloom until the first frosts in balcony boxes or pots. Planted in the ground, it serves as an excellent border plant.

Avoid planting too densely, as the thinner shoots can elongate and collapse. About a month after planting, apply a flowering fertilizer once a week to ensure continuous blooming. However, even without fertilizer, lobelia will still produce plenty of beautiful flowers.

It is advisable to prune the plant twice during summer, especially if grown in balcony boxes or pots, to prevent the plant from becoming too woody.

Propagating Lobelia

Lobelia seedlings are widely available in garden centers in spring at affordable prices. Only plant the seedlings outdoors at the end of May. During the first month after planting, provide some shade to protect the fresh plants from the harsh spring sun.

Propagating from Seed

Propagating Lobelia from seeds can be done from January to March. Maintain a temperature of 64 °F (18 °C) for germination, which usually takes 7-14 days. Seeds can be sown in trays or directly in pots by scattering multiple seeds. Since the seeds need light to germinate, do not cover them with soil.

Seed size: approximately 30,000 seeds/g. To produce 1,000 plants, around 0.5 g is needed.

Pelleted (coated) Lobelia seeds are also available, which makes sowing in trays or seed flats easier, eliminating the need for pricking out. Each pellet produces 3-8 plants, creating a clump similar to grouped seedlings. These clumps can be potted without damage. The pellets are treated with fungicide to protect against seedling diseases. Always ensure that the sowing medium remains moist.

Planting Lobelia Seedlings

If sown in trays, transplant Lobelia seedlings after 4-6 weeks (around April) into 3.5-inch (9 cm) final pots, preferably grouping 3-5 plants together. They can also be planted individually.

Pelleted seeds will naturally form clumps of seedlings. Do not separate these clumps—plant one clump per pot. After a bit of acclimatization (gradually exposing to sunlight), they can be placed in balcony boxes or hanging baskets in May.

After transplanting, maintain a temperature of about 64 °F (18 °C), then reduce it to 54-59 °F (12-15 °C) later on. Dwarf Lobelia varieties usually do not require growth regulators.

Lobelia Diseases, Pests, and Causes of Decline

• It does not tolerate drought, which can cause wilting and drying out.
• If it receives insufficient light, it may grow too tall. In this case, prune it back into a bushy form and move it to a brighter location if possible.
• Overwatering can lead to root rot. To prevent this, use well-draining soil and avoid leaving the plant standing in water.
• Gray mold can affect leaves and flowers, often due to high humidity, poor ventilation, or moisture on the leaves.
• Powdery mildew, a fungal disease, appears as a white coating on leaves and stems. High humidity, lack of ventilation, and wet leaves from overhead watering can cause it.
• Bacterial leaf spot appears as small, water-soaked spots that may enlarge and turn brown or black. Avoid getting too much water on the leaves and remove affected leaves or shoots.

Also known as: lobelia erinus, trailing lobelia, dwarf lobelia, blue lobelia, lobelia pendula