Lobelia cardinalis: plant profile

Scientific classification

Class

Dicotyledons

Division

Angiospermae

Family

Campanulaceae

Order

Asterales

Genus

Lobelia

Species

cardinalis

Key information

Description

Herbaceous perennial with an upright habit visually reinforced by raceme-like inflorescences bearing flowers with cardinal-red petals, present from July to September and popular with pollinating insects such as bees and butterflies. Rustic, it requires a cool, moist substrate or soil. In areas with a cold winter climate it sheds its aerial part and then vegetates again in spring.
Commercially available with an assortment of varieties that differ mainly in the height attained and the colour shade of the foliage.

Origin and history

Curiosities and special features

The botanical genus Lobelia was dedicated by Linnaeus to the 16th century Flemish botanist Mathias de Lobel, while the specific epithet cardinalis refers to the colour shade of the flowers.

The preferred habitat of Lobelia cardinalis is the banks of watercourses where the soil is constantly moist and cool.

Origin and distribution

Species native to a range extending from southern Canada to northern Colombia. By crossing Lobelia cardinalis with other species belonging to the same botanical genus such as L. splendens and L. siphilitica, numerous hybrids(L. x hybrida) have been obtained.

Main features

Flower size

Flower individually is Medium in size, grouped together with others in the Inflorescence.

Leaf

Leaf has a lanceolate lamina.

Flowering period

mid-summer to early autumn for a duration of 30 to 90 days.

Inflorescence

Inflorescence raceme or cluster, borne by a long stem rising from the foliage and assuming landscape value.

Leaf colour

The solid-coloured foliage differs in hue depending on the variety: it can be dark green, dark red, bronze, reddish-bronze, for example, giving additional ornamental value to the plant.

Plant height

The height of the plant varies from 0.6 to 0.9 m, depending on the development of the inflorescences.

Lifespan

Herbaceous Perennial, during the harsh winter it sheds its aerial part and then vegetates again during the following spring.

Where to plant

Its striking inflorescences give it a dominant role in flowerbeds, balconies, borders, terraces.

Stem

The stems are herbaceous; the plant has no thorns.

Flower

The flower is medium-sized, with a tubular corolla and plain petals. It is arranged in large raceme or cluster inflorescences. It flowers from mid-summer to early autumn, with a flowering period of between 30 and 90 days. It is attractive to bees and butterflies.

Growth

Vigorous Growth Plant.

Plant habit

It develops an Erect habitus, visually reinforced by the stems bearing Inflorescences.

Growing conditions

PH

The ideal pH of the medium or growth medium for Lobelia cardinalis varies from slightly acidic to neutral.

Soil preparation

Before transplanting into flowerbeds or borders, carry out light digging, removing any weeds and bulky stones, and proceed by burying organic matter and breaking up coarse clods. If the soil is heavy and compact, bury sand evenly.

Sun exposure

Suitable for full sun, bright shade; for a luxuriant flowering Lobelia cardinalis requires excellent light. To keep the substrate moist and prevent dryness, it is preferable to move the pots into partial shade during the hottest, sultry hours of summer.

Ideal climate and temperature

The ideal temperature is between 18 and 20 °C. It prefers a temperate and cool climate. During the hottest hours of summer, it is advisable to move the pots into partial shade. In winter, protect the roots by spreading a layer of mulch over the soil. If grown in pots, move it to a space sheltered from intense frost.

Use

Appreciated for its showy inflorescences in:

Outdoor ornamental Landscaping

Hardiness

A plant of medium hardiness.

Soil

It requires light, moist and fresh soil; in pots and tubs, use a good quality substrate for spring plants based on peat and perlite. It is essential to keep the soil or substrate constantly moist.

Difficulty

Cultivation is fairly easy with a low level of commitment to maintenance.

Growing tips

Some specific cultivation tips for better vegetative development and abundant flowering:

Always keep the substrate moist Can be planted in sunny or half-shaded beds. With little light the plants will not flower

Combinations with other plants

It is ideal for compact, colourful ornamental compositions, also associated with blooms with different heights in order to create perspective landscape views; colour combinations can include shades of the same or different hues, composing designs and patterns according to personal fantasy. Colour spots or simple borders can be formed with other species such as Bergenia cordifolia, Canna 'Erebus', Hemerocallis, Ligularia dentata, Lysimachia congestiflora .

Care and plant health

Planting

For use in flowerbeds, to be carried out in spring after the risk of late frost has passed, an average density of 7 plants per square metre is recommended in order to ensure the correct development of each specimen, thus obtaining well-proportioned and formally balanced compositions. The sod must be well moistened, it is also suggested to position the plant with the collar outside the soil surface, avoiding excessive compression. Water immediately after planting.

Propagation

Multiplication is mainly by seed, some varieties are propagated by division of the heads.

Watering

Use rainwater, alternatively from the aqueduct, either manually or by means of an irrigation system. Keep the substrate or soil constantly moist but free of water saturation. Prevent dryness. During the summer period ensure that there is water in the saucer.

Fertilising

After proper establishment in the new planting site, on average three to four weeks after transplanting, during the spring-summer period apply a balanced liquid fertiliser specifically for ornamental plants to the substrate or soil and dilute in the irrigation water. Do not exceed the doses and frequency.

The distribution of mature compost at the time of spring planting is recommended.

Edibility and toxicity

Edibility for humans

Non-edible.

Expert advice

Tip

Lobelia cardinalis prefers a constantly cool and moist substrate or soil. In areas with a hot, dry summer climate it is useful to place the pots in partial shade during the middle of the day. During cold winters, protect the roots with a layer of mulch. Remove withered inflorescences.