How to Plant, Grow, and Care for Lobelia

In case your backyard wants extra cool-weather flowers blooming by means of spring and fall, lobelia is a beautiful, low-maintenance plant. The putting clusters of three-petaled flowers and central white “eyes” create a formidable floral show in decorative beds, rain gardens, hanging baskets, and containers. Rising these tender crops is a breeze and rewards you with an abundance of deer-resistant, pollinator-attracting flowers.

The genus Lobelia encompasses a variety of decorative and wildflowers, specifically L. erinus, the trailing tender perennial recognized for its cobalt-blue flowers. True blue is a uncommon shade within the plant world, making this selection additional particular within the backyard. However additionally, you will discover lobelias in lilac, rose, burgundy, sky-blue, and tropical floral colours. There are a whole bunch of Lobelia species, some performing greatest as warm-weather annuals and others as hardy marshy perennials.

Let’s dig into every thing it’s essential find out about caring for lobelia in almost any backyard setting!

Lobelia Plant Overview


Plant Kind Decorative flower Plant Household Campanulaceae Plant Species erinus, cardinalis, siphilitica, and extra Hardiness Zone Varies by species, grown as annual in most temperate zones	Plant Peak Annual varieties as much as 12,” hardy perennials as much as 4’ Companion Vegetation Violas, impatiens, candy alyssum	Plant Spacing 6-18” relying on selection Watering Wants Average, varies by species Solar Publicity Full solar to partial shade Lifespan Tender perennial, typically grown as annual Pests Aphids, slugs, snails Ailments Root rot, grey mould

Historical past and Cultivation

Close-up of a profusely blooming Lobelia with bright blue flowers in a hanging white pot. The plant produces many small tubular flowers consisting of a small upper lip and a larger lower lip which consists of three oval shaped petals. The leaves are dark green, lanceolate, with serrated edges. — Lobelia crops have a wealth of range, with mounding, trailing, and tall varieties obtainable.

With such numerous floral choices, lobelia crops deliver a wealthy botanical historical past to your backyard. There are mounding, trailing, and tall-growing varieties, some remaining perennial and others rising as annuals in temperate zones.

It’s possible you’ll develop the hardy wild lobelias native to the US to draw hummingbirds or plant tender tropical lobelias that cascade from hanging baskets on partially shaded patios. Regardless of your choice, this easygoing group of crops yields intriguing two-lipped tubular flowers and enticing foliage.

What’s Lobelia?

Close-up of a profusely blooming Lobelia with white flowers in a sunny garden. The flowers are small, tubular, bright white. The leaves are bright green, lance-shaped. — With 400+ species worldwide, together with pink, white, orange, and pink blooms, they have been named after Flemish botanist Matthias de Lobel.

Lobelia is a genus of flowering crops within the bellflower household, often known as Campanulaceae. It’s most well-known for its varied hues of sky-blue and cobalt-colored flowers, that are remarkably uncommon in botany. Lower than 10% of flowering crops have blue blooms, together with blue hydrangeas. The distinctly lipped flowers additionally are available in pink, white, orange, and pink.

With over 400 species, lobelias are a various group of crops native to areas worldwide, together with Africa, Asia, and North and South America. The genus bought its title from the Flemish botanist Matthias de Lobel, who first recognized the tobacco-like qualities of the low-growing plant in Flanders, Belgium. Native People used the plant for its natural qualities.

The place Does Lobelia Originate?

Close-up of multi-colored blooming lobelias in a large ceramic flowerpot, outdoors. Plants produce thin, upright stems with spear-shaped green leaves and an abundance of small flowers. The flowers are tubular, bright blue, pale purple and white. — This perennial flower, discovered on each continent besides Antarctica, is most numerous in Australia and Africa.

Lobelia species are native to each continent besides Antarctica, however essentially the most range is present in subtropical and tropical areas in Australia and Africa. Over 30% of all lobelias are native to Africa, together with L. erinus, the most well-liked spring flower in backyard shops.

The North American native wildflowers, Lobelia cardinalis, and L. siphilitica, have been notably utilized by indigenous Penobscot and Cherokee tribes for medicinal functions. Within the 18th and nineteenth centuries, lobelia crops unfold from the Americas and Africa to Europe, changing into fashionable decorative crops in cascading basket shows and royal flower gardens.

Propagation

Relying on the native availability of your required species, you possibly can develop these putting flowers from seeds, cuttings, or transplants from the backyard retailer. Most varieties ought to be planted in spring when the climate has totally warmed. You could plan as much as 12 weeks upfront if rising from seed.

Seed

You may domesticate this dazzling flower from scratch, however it would require some endurance. The tiny lobelia seeds take a number of weeks to germinate and wish particular dealing with. Begin indoors 10-12 weeks earlier than you transplant within the backyard.

Here’s what you’ll want:

Lobelia seeds
Properly-drained seed-starting combine
Small pots or cell trays
Plastic wrap or clear plastic dome (to spice up humidity)
Develop lights or a south-facing window with oblique, shiny gentle
Watering can or spray bottle
Diluted balanced fertilizer

Fill your pots or trays with a evenly moistened seed-starter combine and thinly sow the seeds on the floor. Barely press them into the soil, and don’t cowl them. They want gentle to germinate.

Use a gently spray-nozzle watering can or misting bottle to moisten the soil with out disturbing or transferring the seeds. Cowl the container with plastic wrap or a transparent dome to keep up constant humidity. Guarantee there are nonetheless holes for airflow. In any other case, your seeds might be inclined to damping off illness.

Place the seeds in an space with shiny, oblique gentle or below a develop gentle. Room temperatures between 65 and 70°F are excellent. Germination takes 14-20 days, however a heated germination mat could assist velocity up the method.

Slicing

Close-up of large garden shears near blooming lobelia plants in a sunny garden. Scissors are handheld cutting tools consisting of two metal blades that pivot at a central point. The scissors have a black plastic handle. Lobelia blooms with purple and bright pink flowers. They are small and tubular. — To propagate this perennial plant, take softwood cuttings from wholesome, non-flowering stems in the summertime.

Many species of this genus may be propagated by slicing. In the event you or a buddy has a longtime lobelia plant, that is a straightforward option to multiply your assortment totally free. The most effective time to take softwood cuttings is in the summertime.

This methodology is most typical with the blue or purple trailing lobelia (L. erinus) but additionally works with native species like L. cardinalis or L. siphilitica. This course of can be very acquainted when you have ever rooted petunia cuttings.

Just a few provides are crucial:

A wholesome lobelia plant with non-flowering stems
Sharp, sanitized backyard pruners
Propagation or seed-starting combine
Small pots or cell trays
Misting bottle
Develop lights or a shiny window
Rooting hormone (optionally available)

Discover a lengthy, wholesome stem with a number of units of leaves and no flowers. Flowering stems aren’t viable for cuttings as a result of the plant places its power towards floral manufacturing quite than roots. Inexperienced new progress is one of the best for propagation as a result of it’s younger, pliable, and has many stem cells able to develop into roots and shoots.

Take a slicing about 4-6 inches lengthy, making your lower simply beneath a node. Nodes are the little bumps the place the leaves intersect with the stem. Strip the decrease 1-3 inches of leaves.

Fill your containers with a moist, well-drained combine and place the slicing within the soil, burying about half the stem. Optionally, you possibly can dip the tip of the slicing in a rooting hormone earlier than planting to hurry up the method and forestall rot.

Hold cuttings in a protected space (ideally indoors) with an optionally available humidity dome. The soil ought to be constantly moist however by no means soggy. When new foliage begins to type, and there’s resistance if you gently tug the cuttings, they’re rooted. Lobelia cuttings often take 24 to 30 days earlier than they’re able to transplant, so take a bunch directly!

Division

Close-up of female hands in white gloves dividing lobelia seedlings in a flower pot for propagation. The plant has green glossy spear-shaped foliage with serrated edges. The flowers are small, tubular in shape, blue in color, consist of a small upper lip and a larger lower lip consisting of three petals. — Dig up the basis balls and lower them into clumps to divide this perennial plant within the spring. Permit them to determine earlier than winter.

Perennial lobelia species may be divided within the spring by digging the basis balls and slicing them into clumps. This ensures the crops have your complete rising season to determine themselves earlier than the chilly units in.

To divide your lobelia:

Water the plant a day or two earlier than division.
Moistened soil will make it simpler to elevate and separate the roots with out damaging them.
Rigorously dig across the plant’s base with a backyard fork or shovel.
Carry the plant from the bottom.
Use a pointy, clear knife or pruners to fastidiously separate the basis clumps into sections.
Guarantee every 4-6” part has loads of roots and foliage.
Prune away any broken or unhealthy components of the leaves and roots.
On the identical day as dividing, transplant new clumps into containers or a brand new mattress.
Change the unique plant and backfill the soil.
Make sure the planting holes are deep sufficient for the roots to unfold.
Plant on the similar depth and gently fill the lodges with soil.
Hold new divisions constantly moist and add a little bit of all-purpose balanced fertilizer.

Division is a good way to skinny out an overcrowded stand. Overcrowding could cause competitors for vitamins, water, and daylight, resulting in plant stress or illness. Use the spacing information under to make sure the crops can develop to their full glory.

Planting

Whether or not you bought a longtime nursery plant or began your personal lobelia, the transplanting course of could be very easy.

Find out how to Transplant

Close-up of female hands planting lobelia seedling in the garden. The plant has lush bright green glossy foliage and small blue flowers. The leaves are spear-shaped, with slightly lobed edges. The flowers are tubular in shape, consist of a small upper lip and a larger lower lip. — For this plant, select spring for transplanting, keep away from peak summer season warmth, and guarantee well-drained soil with compost.

The most effective time to transplant is within the spring when the danger of frost has handed. If rising in a container, you possibly can plant a bit earlier so long as the association is protected. Keep away from planting within the peak warmth of summer season, or the crops will develop into burdened.

Select a location with well-drained, moist soil and loads of compost. Cardinal flower lobelia is an exception to this rule as a result of it tolerates marshy, streambank areas. Completely hydrate the seedling a day or two earlier than transplanting to cut back the danger of transplant shock.

Dig a gap about twice as deep and vast as the present rootball. Gently loosen the plant from its nursery pot and place it within the gap, sustaining the identical soil stage. Backfill the outlet and evenly tamp all the way down to safe the plant. Preserve steady moisture in the course of the first few weeks to assist it get established.

Optionally, mulch perennial lobelias to suppress weed competitors, retain soil moisture, and add additional heat.

Spacing

Close-up of female hands in white gloves planting seedlings of blooming lobelia in a flower pot with soil. The seedlings have vertical thin stems covered with spear-shaped green leaves with serrated edges. The flowers are small, tubular, blue-purple. — Spacing necessities for these perennial flowers fluctuate by species.

The spacing required for these flowers varies broadly between species. Shut spacing can create large, lush clumps of foliage and flowers, however planting too shut could cause illness points or stunt plant progress. Relying in your backyard mattress or container measurement and selection, it’s possible you’ll must experiment.

Listed here are the basic spacing wants for every kind of lobelia:

Upright lobelia (L. erinus): 6-8 inches aside, dense plantings look nice in containers
Trailing lobelia (L. pendula): 8-12 inches aside in hanging baskets
Cardinal flower (L. cardinalis): 12-18 inches aside. Taller crops are nice for borders
Indian tobacco (L. siphilitica): 12-18 inches aside, excellent for native woodland gardens

Find out how to Develop

Rising lobelia could be very easy, and the crops don’t often have many points. The native species are essentially the most hands-off, whereas the tender perennials require a bit extra upkeep to maintain them blooming in container or basket shows.

Gentle

Close-up of Blue violet lobelia flowers in summer garden. The plant forms upright stems covered with small spear-shaped leaves of bright green color. The flowers are small, tubular, purple, growing along the stems. — For these perennial crops, intention for keen on full solar situations, offering 4-6 hours of direct daylight day by day.

Keen on full solar is right for nearly all lobelias. Guarantee your plant has a minimum of 4-6 hours of direct daylight day by day and a few afternoon shade in scorching climates. Cardinal flowers and Indian tobacco tolerate extra shade and may thrive in woodland areas.

When deciding on your planting location, contemplate how the solar strikes over the realm all through the day and season. For instance, a dangling basket on an east-facing porch will obtain plenty of morning daylight and afternoon shade, which is superb for an extended flower show. An excessive amount of intense afternoon gentle can wither the delicate flowers and dry out the potting combine extra shortly.

If rising clumping or trailing varieties within the floor, plant them alongside different low-growing crops in order that they don’t get fully shaded out or baked by the recent solar.

Water

Lobelia wants constantly moist soil. You need to by no means let these crops dry out! For container-grown lobelia, water 2-3 occasions per week after checking the soil moisture. If the highest inch is dry, it’s time to offer your flowers a drink. Drainage can also be vital so the plant roots don’t develop into soggy or rotten. Perlite and vermiculite guarantee water doesn’t pool inside a pot or basket.

Native species notably want moist to moist soil, as they thrive in marshy areas. They want water a couple of times every week throughout institution. Nonetheless, waterlogging could cause rot points, so take care to not over-irrigate, particularly in the event you reside in a wet local weather.

Soil

Close-up of Lobelia erinus seedlings in a pot filled with potting mix. Seedlings are small, composed of vertical short stems and small, round, smooth, pale green leaves. — Use well-drained, loamy soil enriched with compost or high quality potting combine, and guarantee good soil aeration.

Loamy, well-drained soil is right for this plant. Amend with compost or a high-quality potting combine to yield the brightest flower show. Earlier than planting, loosen the soil with a backyard fork or your arms.

In case your soil has poor drainage, add peat moss, compost, perlite, or vermiculite so the roots can breathe correctly. In a container, an ordinary flower potting combine works nice.

The pH can vary from 5.8 to 7.0, with most species preferring barely acidic soil. A layer of shredded straw or leaf mulch can defend the soil from drying out and assist scale back weed competitors whereas concurrently moderating the soil temperature.

Local weather and Temperature

Close-up of blooming purple and pink lobelia in the garden. The plant produces many small tubular flowers that consist of two lips, the lower one consists of three petals, and the upper one is less pronounced and consists of smaller two modified petals. The leaves are narrow, small, lanceolate, with serrated edges. — These perennial flowers thrive in delicate temperatures between the 60s and 70s.

These flowers get pleasure from good delicate temperatures within the 60s and 70s. Most lobelias are native to subtropical and tropical areas of the world, that means they’re solely tender perennials in many of the United States.

For instance, the favored L. erinus (trailing blue lobelia) is often grown as an annual flower in spring and fall. It can’t deal with temperatures under 40°F and usually stops flowering when temperatures dip under 50°F.

In order for you a extra cold-hardy selection, Lobelia x speciosa cultivars are perennials hardy to a whopping 5°F. Equally, the North American native species Indian tobacco and Cardinal flower can deal with damaging temperatures throughout their dormant section and nonetheless develop again the next yr.

Do not forget that these are often herbaceous perennials, in order that they die again to the bottom at frost and regenerate their foliage within the spring. Mulching may also help defend the basis clumps by means of harsh winters.

Fertilizing

Close-up of lobelia erinus flowers blossoming in a flowet pot. The flowers are small, tubular in shape, purple and pale blue. The leaves are small, narrow, dark green, spear-shaped, with serrated edges. — A balanced all-purpose fertilizer works nicely, however keep away from extreme nitrogen to stop extreme foliage progress.

A balanced all-purpose fertilizer is completely positive for these two-lipped blossoms. The crops aren’t notably demanding about vitamins so long as they don’t get an excessive amount of nitrogen. Extreme nitrogen causes an overgrowth of lush foliage on the expense of flowering.

A diluted slow-release natural fertilizer may be utilized within the spring and each 3-5 weeks in the course of the rising season. Vitamins leach out of containers extra shortly, so it’s possible you’ll must fertilize each 2-3 weeks. In the event you plan to overwinter your perennial lobelias, cease fertilizing the autumn to permit the plant to organize for dormancy.

Observe package deal directions fastidiously and apply diluted fertilizer straight on the soil stage. By no means put fertilizer on the plant’s foliage, or it could burn them.

Upkeep

Close-up of a flowering lobelia plant in a large hanging pot on the porch next to the lantern. The plant has hanging stems with small green leaves that are lance-shaped and slightly serrated. The flowers are small, blue-violet. They are tubular in shape, have two lips, and the lower lip is larger and more pronounced than the upper. — The trailing sorts want the least pruning, whereas upright varieties profit from common pruning.

These low-maintenance crops don’t have to be tended to tremendous typically. Trailing varieties want the least pruning, whereas upright cultivars profit from common pruning of straggly progress.

Constant deadheading encourages essentially the most distinguished, neatest flower arrangements. Deadheading redirects plant power towards producing new blossoms quite than going to seed. When flowers fade, pinch them off or lower them with pruners on the stem base. Take away any lifeless or broken foliage presently.

If a plant turns into leggy or overgrown, you possibly can reduce the crops by as much as one-third to encourage bushier new progress.

Native Pollinator Vegetation

Close-up of Turtlehead (Chelone) flowering plants in a sunny garden. The leaves are opposite, lance-shaped, and have serrated edges. They are dark green and grow along sturdy stems.The flowers of the Turtlehead plant are the standout feature. They are tubular and resemble the shape of a turtle's head. Flowers are delicate pink. They are arranged in dense, upright spikes at the top of the stems — Native plant fanatics will recognize the cardinal flower of their gardens, because it attracts butterflies, bees, and hummingbirds.

For native plant fanatics and pollinator lovers, the cardinal flower (L. cardinalis) is a pleasant addition to your butterfly, bee, or hummingbird backyard.

Plant it alongside different native, moisture-loving flowers like:

Swamp milkweed (Asclepias incarnata)
Turtlehead (Chelone spp.)
Blue flag iris (Iris versicolor)
Pickerelweed (Pontederia cordata)
Bee balm (Monarda spp.)

Varieties

The variety of choices on this genus may be overwhelming. First, resolve what peak lobelia you want:

Clumping (low-growing): L. erinus or L. puberula
Trailing (hanging baskets): L. pendula
Upright (tall border beds): L. siphilitica or L. cardinalis

Subsequent, decide in the event you’d prefer it to develop as an annual or perennial:

L. erinus and L. pendula are tender perennials often grown as annuals in zones 4-9
L. cardinalis is a local hardy perennial in zones 3-9
L. siphilitica is a local clumping perennial hardy in zones 4-8

Listed here are a few of our favourite varieties for the prettiest show:

Upright Lobelia (L. erinus)

Lobelia 'Crystal Palace' is a herbaceous perennial known for its compact growth habit and striking appearance. It boasts dark green foliage that forms a lush carpet, and atop its sturdy stems, you'll find clusters of small, deep blue-violet flowers that create a vibrant contrast. — ‘Lobelia Crystal Palace’ is prized for its deep blue-violet flowers and compact progress behavior.

These varieties are mostly used as bedding, edging, or container crops. They develop 6-12 inches tall and flower all spring and fall.

You could find cultivars with blossoms of each shade, however the most well-liked is blue. My favorites embrace:

‘Crystal Palace’
‘Regatta Sequence’
‘Cambridge Blue’
‘White Girl’

Trailing Lobelia (L. pendula)

Lobelia 'Sapphire' is a charming herbaceous perennial celebrated for its compact growth and captivating aesthetic. It features rich green foliage that forms a neat mound, serving as an elegant backdrop to the star of the show—its stunning sapphire-blue flowers. These delightful blossoms gather in clusters atop sturdy stems, creating a striking contrast against the lush foliage. — ‘Lobelia Sapphire’ is thought for its putting sapphire-blue flowers and is a favourite for including vibrant shade to hanging baskets.

This vining species is right for hanging baskets or window planters the place the vines can cascade downward. They develop 6-12 inches tall and may unfold 12-24” in each route.

The prettiest container varieties are:

‘Sapphire’
‘Waterfall Sequence’
‘Fan Scarlet’

Native Lobelia Species

The Cardinal flower (Lobelia cardinalis) is a captivating herbaceous perennial that stands out with its striking appearance. It showcases lance-shaped, deep green leaves that provide an elegant backdrop for the vibrant, cardinal-red flowers. These brilliant blooms are arranged in tall, spiky clusters atop sturdy stems, creating a visually stunning contrast against the lush foliage. — The cardinal flower is well known for its good pink blooms and talent to draw hummingbirds to the backyard.

If you wish to develop a local planting or begin a wildflower backyard, these species are indigenous to the US. They appeal to plenty of pollinators and have a tendency to have a bigger progress behavior.

Cardinal flower (L. cardinalis)
Indian tobacco (L. inflata)
Nice blue lobelia (L. siphilitica)
Downy lobelia (L. puberula)

Pests and Ailments

Whereas splendidly deer and rabbit-resistant, lobelia crops generally fall sufferer to aphids, slimy pests, and fungal ailments. Thankfully, they’re straightforward to take care of.

Aphids

These small sap-sucking bugs spare no victims within the backyard. They assault virtually every thing, together with your decorative flowers.

In the event you discover aphids on the undersides of your lobelia leaves, you possibly can wipe them off with a diluted neem answer or spray them with a heavy stream of water, taking care to not harm the flowers. Interplanting with white alyssum and marigolds may also help appeal to organic predators.

Slugs and Snails

Close-up of a snail on blooming lobelias in a sunny garden. Snail has a soft, coiled shell and a slimy, elongated body, brown in color. The plant produces an abundance of tiny bright blue tubular flowers with 4 petals. — Moisture-loving crops like this typically appeal to slugs and snails that may hurt new transplants and create irregular leaf holes.

Given the moisture-loving nature of this plant, slimy pests typically hang around close to their base because it offers the best situations for them to thrive. Slugs and snails could cause points with new transplants and chew irregular holes within the leaves.

Use iron phosphate slug bait or beer traps to seize slugs. You may also sprinkle diatomaceous earth across the base of the crops, however you will want to reapply after it rains.

Root Rot

In case your plant leaves are wilting regardless of loads of water, it could have developed a nasty case of root rot. You may typically detect a foul odor from the basis zone in container-grown crops, though that’s often not a symptom for in-ground or mattress plantings. The roots will seem like brown or black and could also be mushy in the event you dig up a plant. Waterlogged soil and over-irrigating are the important thing elements that trigger fungal growth that may assault your crops’ root techniques.

It’s often not price it to save lots of a plant with root rot except you catch it very early and may trim off solely a small quantity of the basis system to take away the rotten tissue. Usually, get rid of the plant and begin a brand new one with additional well-drained soil amendments (like perlite and vermiculite) and rather less water. Compost also can alleviate moisture accumulation points.

Mildews

Close-up of the base of a plant affected by Gray Mold. The stems and leaves of the plant are brown, completely covered with moldy moss of a white-gray hue. — Mould can develop on lobelia flowers in humid areas, probably harming them.

Various kinds of mildew (downy mildew, powdery mildew) can type on these crops in humid climates. Not solely is it unpleasant, however it could possibly kill a plant if it will get out of hand. To forestall mildew, keep away from watering your lobelia from the highest. As a substitute, water on the base of the crops so the foliage doesn’t get moist. In humid climates, widen the spacing to encourage extra airflow.

Most mildew is treatable if it’s caught early sufficient. Trim off severely broken foliage and spray the remainder of the plant with a copper or sulfur-based fungicide. If the plant is already totally engulfed in mildew, take away it and throw it away; don’t compost it, because the fungal strains that trigger these mildew ailments can persist within the compost pile.

Plant Makes use of

Close-up of a flowering lobelia plant in a large hanging pot, outdoors. The plant is lush, has thin curly stems covered with small green leaves of a lanceolate shape. The flowers are small, tubular in shape, blue and pink. — Lobelia is principally grown for decorative functions in hanging baskets, planters, and gardens.

Lobelia is primarily used as a decorative flower in hanging baskets, planters, and backyard beds. Native varieties appeal to pollinators and add vibrant magnificence to any panorama setting, particularly wildflowers or rain gardens. The distinctive blue flowers are uncommon and exquisite in floral preparations.

Whereas some lobelia sorts have been traditionally utilized in herbalism, the plant is taken into account mildly poisonous to animals and other people. It’s greatest to maintain it as a decorative.

Remaining Ideas

Any moist, partially sunny backyard or patio space is the proper spot for lobelia. This genus of crops has roots everywhere in the globe and provides spectacular splashes of uncommon blue flowers to your spring and fall decorative beds.