Lobelia erinus: How to plant, grow and care

Lobelia erinus is a low-growing, herbaceous perennial flowering plant in Campanulaceae. It is native to Asia but can be found in most regions of North America.

The blossoms are blue to violet in wild plants, with a five-lobed corolla 8–20 mm across. Around 0.5 to 4.5 inches long, inflorescence stems are 5 inches long. The hermaphrodite flower is zygomorphic with up to 1-centimeter length and quinate with a twofold perianth. The five sepals are intertwined. L. erinus has two stamen and two stigmas.

For more than 200 years, the delightful floral accents of Lobelia have been helping gardeners to bring a bit of variety to their flower beds. The common Lobelia is a perennial with an interest in spreading, growing best when planted in containers or given plenty of room to roam free. Its trailing branches reach out as far as possible and will trail along the ground if given a chance.

Lobelia erinus is one of the most common species used for floral design in traditional floral art forms, and it is often referred to as the “blue lobelia.” Even though it’s a native of North America, many people swear that its beautiful blue color, distinctive shape, and leafy habit make it perfect for any natural landscape design. Although it is classified as an annual, this perennial flower can survive in colder regions during the winter months in areas like Zone 7b.

The little-known secret about lobelia flowers is that they are one of the best flowering plants for attracting winged or flying insects such as bees and butterflies.

Lobelia erinus
Lobelia erinus flowers

Lobelia erinus plant facts

Common Name: Dew flower Scientific 

Family: N/A Native

Origin: Mexico, Guatemala, Honduras, and other parts of South America Foliage 

Color: Pink to purple Foliage, Yellow or orange flowers, or both

 Flowering Periods: Spring & Summer 

Soil Type: Moist soil conditions 

Growth Rate: Slow

Water Requirements: Like most plants, it needs reasonable amounts of water. It needs moderate to high water requirements.

See Also: Monstera Plants

Lobelia erinus common names

It is also known as Lobelia cardinalis, Lobelia ciliaris, Lobelia fulgens, Lobelia fruticosa, Lobelia grandiflora, and others.Its Scientific name is Lobelia. The plant’s scientific name comes from the Latin words “lobilus,” meaning ‘little frog,’ and “erus,” meaning ‘ear.’ It was named due to its resemblance to a bit of a frog’s head, with elongated lips.

How many varieties of Lobelia are there?

There are more than 400 species of plants in the genus Lobelia. However, the species known as Lobelia is only grown for its deep blue flowers. The variety of colors would make anyone think that it’s more than one species, but just one kind of Lobelia is called “Lobelia erinus.” This species has been known by many names such as Lobelia cardinalis, Lobelia ciliaris, Lobelia fulgens, Lobelia fruticosa, Lobelia Grandiflora, and many others other names, each recognizing a specific variation.

Lobelia erinus annual or perennial?

Generally, it is considered a perennial that lives for at least 2 years. The lobelia plant does not require much maintenance and only needs to be watered occasionally during dry periods. This plant can grow up to four feet tall and spread up to four feet wide. If planted in the backyard, it can form a beautiful blanket of flowers in the summer months.

Types of situations where lobelia erinus grows well

Lobelia erinus grows well in open grasslands and disturbed areas with sparse vegetation. It does best in full sunlight and prefers moist, acidic soil. Aged manure or compost is an excellent fertilizer for this plant. The plants can grow up to 15 inches tall and bloom throughout the summer months.

How to grow lobelia erinus from seed?

To germinate the seeds:

  1. Soak them in water for 24 hours.
  2. In a glass jar with a lid, place the seeds and place the pot in water. The jar should be placed on a shelf or table to be at a level where it will remain at least 1/2 inch above the water during germination.
  3. Move the jar twice during this period to ensure that they are well saturated.

To start transplanting lobelia erinus into small pots, sow them in late summer or fall as soon as possible after preparing the seed. The seeds need light to germinate, so sow directly into pots with about 1/4 inch of soil or mix them with sterilized sand to create an ideal medium for germination. Use a sterile potting mix that contains peat and vermiculite, sand, and perlite. A good mixture is equal parts of coarse sand, peat moss, and vermiculite. Sow the Lobelia erinus seeds approximately 3 mm deep in the medium and place the pots in a warm area to germinate.

How to grow lobelia erinus from seed in a greenhouse?

To grow lobelia erinus from a greenhouse, sow the seed directly into pots or trays containing a sterile growing medium such as sand or compost with equal parts of perlite or coarse timber bark. Sow three seeds about 1 cm deep every six inches apart in each pot or tray.

When the seeds germinate, move them to a warm location that has at least 6 hours of direct sunlight each day to spend the first two seasons. As seedlings grow, change the light as needed. Once they are 2 or 3 inches tall, they begin to focus their attention entirely on sunlight and keep them away from drafty areas.

How to take care of lobelia flowers?

The care of lobelia flowers is usually relatively easy, but it should be remembered that lobelias are unlikely to survive the winter in most temperate regions. The best advice is to plant them where they are intended to remain for at least two years (they sometimes grow for up to ten years) and to provide some temporary protection in the form of a reasonably thick mulch through the winter. As with other tender plants, they must never freeze in autumn as this will kill them. In addition, they appreciate compost or well-rotted manure added every spring and do not require any pruning or staking. Cuttings can do propagation in the spring and summer.

Lobelia erinus medicinal uses

Used to relieve a hangover

Lobelia is also known as ‘Dew flower’ because of its ability to cure various ailments ranging from headaches, upset stomach, and dizziness. It has a bitter taste which gives it the ability to heal faster than other plants. It contains many different healing extracts such as flavonoids, tannins, and minerals like iron, magnesium, phosphorus, etc., that make it beneficial for curing heart diseases and liver problems.

Used as a laxative for the stomach and intestines

It has been known to cure various digestive problems such as constipation and dysentery, especially in women. It helps in clearing the blood and provides relief from bellyache.

Used to treat the liver problem

It is known as a ‘life saver’ for people with gallstones, jaundice, and hepatitis. It is also known to increase the flow of bile and help break down food particles.

Used to treat lung problems

Lobelia is known to cure asthma as it increases oxygen flow in the lungs. It also helps in improving blood circulation and relaxes the muscles of bronchial tubes. With this being said, drinking lobelia tea can be an ideal way of treating lung diseases such as bronchitis and tuberculosis.

Used to treat heart-related problems

It is known to increase blood flow throughout the body and is often recommended for heart patients. It also relaxes muscles in the blood vessels and can cure chest pain.

Used as an anti-fungal agent

The juice extracted from its leaves helps treat ringworm as it contains an ingredient known to kill fungi. It has been found to cure nail fungus and athlete’s foot. Its seeds are also known to cure ringworm.

Lobelia erinus is known to be effective in treating sore throats and coughs

The high flavonoids in its leaves have been proven to have a soothing effect on the throat and help treat cold symptoms. It has also been known to destroy bacteria that cause sore throats and coughs, so it’s an ideal cure for these conditions.

Lobelia erinus also acts as a mosquito repellent

The plant’s scent acts as a natural mosquito repellent and can help prevent many diseases from occurring by keeping disease-carrying insects at bay.

Lobelia erinus hardiness zone

This Lobelia is hardy in zones 10-11 but treated as annuals in areas with less warmth.

If foliage and blooms significantly decline in summer, cut back to encourage fall bloom.


We hope you find this article about lobelia erinus very useful for your gardening and health. If you have any questions, please leave a comment below. Lobelia erinus is ranked among the top 100 most gorgeous flowers globally by the botanical garden.