Lobelia Plant: An Outdoor Plant

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Lobelia is a plant that flowers genus with 415 varieties found mainly in tropical to warm temperate parts of the world, with a few species extending into cooler temperate zones.  They are frequently called lobelias.

A large and small annual, perennial, and shrubby plant known as lobelia is found in many different locations and comes in a wide range of hues. There are many species that seem to differ greatly from one another. However, they all have straightforward, alternate leaves and tubular, two-lipped blooms with five lobes. The lowest three lobes may be spaced apart, with the upper two lobes perhaps standing up. They have a bright bloom color and profuse flowering, which adds to their appeal as garden ornaments.

Lobelia Plant

In the majority of USDA zones, lobelia (Lobelia erinus), a delicate annual, is grown as an annual. It often resides in the nursery’s section of annual plants and has several garden uses. However, lobelia spreads quickly.

Most lobelia types have a trailing growth habit, while some clump. Although there are many flower colors available, it is well known for having a real sky-blue tint. The colors offered include lilac, pink, lilac, white, and purple. Most variants have a tiny white “eye” in the center of their blossoms. Although the majority of the cultivars have green foliage, a small number have leaves that have a faint golden hue.

Lobelia Plant Overview

Common Name:Lobelia, yearly lobelia, edging lobelia, and laguna flower are numerous instances of lobelia.

Botanical Name: Lobelia erinus

Family: Campanulaceae

Plant Type: Annual

Mature Size: 6 -9 in. tall, 9-10 in. wide

Sun Exposure: Full, partial

Soil Type: Moist but well-drained

Soil pH: Acidic, natural

Bloom Time: Summer, fall

Flower Colors: Blue, pink, purple, white, red

Hardiness Zones: 10-11 (USDA)

Native Area: Africa

Toxicity: Toxic to people, toxic to pets

Types Of Lobelia

The term “lobelia” is used to refer to a variety of plants. Some are tough perennials, While some are hardy perennials, others are various species of the delicate perennial Lobelia erinus, which is usually grown as an annual. There are several colors to pick from depending on the type of plant you decide to grow.

Cardinal Flower:  Hummingbirds love this hardy annual with red flowers and a straight growth style; it reseeds quickly.

Great Lobelia:      Recurrent with blue blooms and an erect growth style.

‘Laguna’ lobelia erinus’: Researchers created this tender perennial with blue flowers and a trailing habit that can endure hot summers better than other trailing lobelias.

Lobelia erinus ‘Alba’: Delicate plant with white blooms that trail.

‘Lilac Fountain’ Lobelia erinus: On a delicate perennial with a hanging habit, there are white blossoms.

Lobelia erinus ‘Rosamund’: Trailing cherry-red perennial with hardy flowers.

Which Season Can You Grow Lobelia Plant?

The colder months are when lobelia blooms the most, from spring through October.

How To Grow Lobelia Plant

Raising lobelia from seed is simple and inexpensive, as with other annual flowers. You will have more success using sources than other methods of spreading lobelia. You’ll also have a broader range of kinds when growing from seed rather than nursery plants.

In cold-winter areas, start lobelia seeds indoors 6 to 8 weeks before your area’s expected last frost date. In mild-winter places, plant the seeds outside in early spring as long as overnight temperatures remain consistently above 50 degrees Celsius.

Spread the tiny seeds evenly on a seedling tray filled with seed-starting soil. However, do not bury the seeds.

Place the uncovered tray near a window that gets enough light.

To hydrate the soil, sprinkle the tray with water.

Continue applying water to the soil daily, or as needed, to keep it wet but not waterlogged. Two to three weeks after seeding, the seeds should begin to germinate.

It’s time to plant your lobelia in the garden if the nighttime temperature is regularly above 50 degrees Celsius. To begin, gently harden off the plants to allow them to acclimatize to the outside environment. Then, carefully separate the seedlings, being careful not to harm their roots, and plant them in the appropriate area outside, whether in the ground or a container.

Plant yearly lobelia plants 4 to 6 inches apart in pots and somewhat more apart in the soil.

Lobelia Plant Care

Although Lobelia erinus is a sensitive perennial that may survive the winter in USDA zones 10-11It is often grown as an annual and dies after its blooming season. Despite its tiny, fragile look, lobelia requires little care. It does not require removing since the plant cleans itself of wasted, small flowers. It is also not eaten by deer. Though lobelia is usually a plant that loves more light than shade, it does suffer when exposed to full sun during sweltering summers. If this happens to your plant, you may revive it by pruning it and supplying regular water.


An annual or perennial flowering plant with no need for maintenance is lobelia. Numerous smaller annual lobelias that are in bloom are self-cleaning and do not require deadheading. To encourage new growth, lobelia plants might benefit from deadheading, trimming, or sporadic cuts during the growing season. To be ready for fresh growth the following year, perennial lobelias can be clipped all the way to the ground in the late winter or fall. Perennial lobelias may benefit from maintenance pruning and deadheading throughout the growing season to maintain an attractive look.

Remove spent flowers and trim spent flower stems at an angle.

Remove stems and blossoms as they dry back.

Cut back forcefully if your lobelia loses its habit, becomes lanky, or seems drooping to encourage new growth.

Why Prune Lobelia Plant

Pruning lobelia is mostly done for general upkeep, as well as for overall health and beauty. As the plant develops and blooms throughout the season, the discarded flowers should be cut off to encourage new development and blooming. When lobelia becomes lanky or out of control with drooping, open behaviors, they should be pruned in addition to deadheading. Lobelia is given an opportunity to recover by being pruned. Pruning may assist to remove unhealthy portions from the plant if your lobelia is stressed as a result of insect or disease pressure.

Lobelia Pruning Tips

You shouldn’t prune a lobelia that has just been planted.

Plan to deadhead or clip your flowers regularly

To encourage new growth, cut back to the ground.

After the season, trim down unwanted growth.


Gardeners like the evergreen perennial lobelia for its vibrant blossoms and ability to draw hummingbirds and butterflies. While some varieties are native to the country, others have been bred to do well in our gardens. The perennial lobelia may also be cultivated from seeds, and it can be divided into new plants by splitting apart clumps of the existing plant Trim the Lobelia in the late spring. Only the recent growth that hasn’t yet bloomed should be removed.

Cuttings should be free of leaves. Use your garden shears to cut a few 4 to 5-inch sections of stem growth from the donor Lobelia plant. Cuts should be inserted into the muddy earth. The majority of the incisions should be visible above ground. Water the pot every other day. Cuttings must be stored in a continually moist environment in order to set. Lobelia is a dependable perennial that is a favorite of gardeners due to its lovely blossoms and ability to attract butterflies and hummingbirds.


The ideal soil for lobelia is wet and well-drained. Don’t allow the environment to grow too wet, though, since this might result in root rot.


Maintain dry but not wet soil with a consistent moisture level. You may not need to offer more water in places with frequent rainfall. In more parched areas, though, expect to water your lobelia every few days during the summer, and more frequently if the weather gets scorching.


Because lobelia is an abundant blooming and heavy feeder, fertilizing it every two weeks with a liquid fertilizer for flowering plants will result in the most excellent results. These are often more wealthy in phosphorus than nitrogen and potassium since phosphorus encourages more blossoms.


Since lobelia isn’t fussy about sunlight, it can grow in conditions ranging from light shade to direct sunlight. Place lobelia in a location where it will only receive early sunlight if your summers are exceptionally hot. Shade to partial shade in the afternoon. Grow it in full sun (as long as you water it frequently) in places with warmer summers to get the most produces flowers.

Temperature and Humidity

The spider mite is the principal insect that can harm lobelia. Light cold water sprays can be used to treat a minor spider mite infestation. In the event of a serious infestation, insecticidal soap, neem oil, or insecticides may be used as a last option. Lobelia is also a favorite of maize earworms, and when they bite holes in the leaves, the plant may become susceptible to fungus-related ailments. Corn earworms can be removed manually and with the use of pesticides before too much harm is done.

Pests And Diseases

The illness begins as leaf spots and progresses to a blight. The following signs of bacterial blight on Lobelia include: A prominent brown border surrounds the early leaf dots on the blooms and leaves of Lobelia plantlets. An aged leaf’s edges may develop leaf spots.

Common Problem With Lobelia

Because of different diseases and light sensitivity, this sensitive plant might have its share of issues.

Browning Foliage

With lobelia, excessive watering is a common problem. You risk overwatering it because it doesn’t like the heat, which will turn the leaves brown. On the other side, lobelia becomes brown in hot weather. If the lobelia is in a pot but drying out in the sun, try moving the container to shade or providing temporary shade.

Leaves Curling

Both warm temperatures and excessive dryness can harm lobelia. The leaves may become black and curl up at the margins to protect themselves if the plant is subjected to dryness. Give the plant more shade and water, just as you would with withering foliage.

Spotted leaves

Mites can harm the plant by draining liquids from its leaves, causing them to become spotty. When you see some spots, apply insecticidal soap to treat the problem.

Brown Base

If the base of the mound appears to be browning but the surrounding foliage isn’t, you may have maize earworms, another type of bug infestation. This could be challenging to correct if the damage (holes in the leaves) has already been done. It is crucial to remove damaged regions as soon as possible to stop the issue from worsening since the damage may make the plant susceptible to fungal diseases.

Benefits Of Lobelia

Numerous alkaloids or chemicals found in lobelias have medicinal or therapeutic properties. Some well-known alkaloids include morphine, nicotine, and caffeine. The most important alkaloid in Lobelia inflate, lobeline, may offer protection from the following illnesses. Asthma and other breathing-related conditions,

ADHD (attention deficit hyperactivity syndrome),


Drug abuse,

Antioxidant power,

Dosage, Side Effects, And Safety

Due to the low amount of study, there are no recommended doses or guidelines for lobelia. One study on ADHD patients found that tablets containing up to 30 mg of Lobeline per day appeared to be safe.

However, other negative consequences include nausea, a bitter aftertaste, tongue numbness, irregular heartbeat, and high blood pressure.

Furthermore, lobelia has been associated with vomiting and can be fatal or even lethal when taken in extremely high doses. The deadly portion of the leaf ranges from 0.6 to 1 gram, and 4 grams may be fatal.

Due to a lack of safety studies, children, people on medicines, and pregnant or nursing women should not use lobelia products.

The quantity of the product may vary from what is stated on the label because the FDA does not carefully regulate supplements. Always choose supplements that have undergone independent review.


A flowering plant called lobelia has been utilized for medicinal purposes for decades.

According to some studies, the active ingredient in Lobelia inflate, lobeline, may help cure conditions including drug abuse, depression, ADHD, and asthma.

However, there is little human research, and high doses of lobelia may have fatal side effects. Many would suggest avoiding lobelia in most circumstances due to the paucity of research and the numerous unfavorable side effects.



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