The Cardinal Flower

Mar 9, 2026 | Live Plants

Lobelia cardinalis

Lobelia cardinalis Overview

Scientific Name: Lobelia cardinalis
Common Name: Cardinal Plant / Cardinal Flower
Origin: North and Central America
Plant Type: Stem plant
Height: 20–50 cm
Difficulty Level: Easy to moderate
Lighting Requirements: Low to moderate
Temperature: 20–28°C

Lobelia cardinalis, often known as the Cardinal Plant, is a popular aquarium plant valued for its bright green leaves and upright growth. In its natural form it grows along riverbanks and wetlands in North and Central America, where it can grow both submerged and above the water surface.

In aquariums, Lobelia cardinalis is appreciated for its clean, structured appearance. When planted in groups it can create attractive midground or background planting areas, adding height and texture to planted aquariums.

Aquarium Requirements for Lobelia cardinalis

Lobelia cardinalis is considered a relatively hardy plant and can adapt to a range of aquarium conditions when provided with stable water parameters.

Typical aquarium conditions include:

  • Lighting: Low to moderate lighting

  • Temperature: 20–28°C

  • pH Range: Around 6.0 – 7.5

  • Placement: Midground or background

  • Growth Rate: Moderate

This plant benefits from nutrient-rich substrates and regular fertilisation, although it can still grow successfully in many standard community aquariums.

Growth and Appearance

Lobelia cardinalis grows as an upright stem plant with rounded green leaves that grow along the stem. When grown submerged in aquariums it maintains a compact structure, while in emersed conditions the plant can develop striking red flowers above the water surface.

In aquariums it is most commonly used to create structured plant groupings, particularly in natural aquascapes or planted community tanks.

Regular trimming can help encourage bushier growth and maintain the desired shape within the aquarium.

Care and Maintenance

Lobelia cardinalis is generally easy to maintain with basic aquarium plant care.

Helpful care practices include:

  • Providing stable lighting conditions

  • Using nutrient-rich substrate or root fertilisers

  • Regular trimming to maintain shape

  • Consistent water parameters

While CO₂ injection is not essential, it can encourage faster growth and more compact plant development in heavily planted aquariums.

Aquascaping with Lobelia cardinalis

This plant works well in a variety of aquascape styles and aquarium layouts.

Popular uses include:

  • Midground planting groups in planted aquariums

  • Structured rows in aquascaped layouts

  • Natural river-style aquariums with driftwood and stones

Its upright growth habit makes it useful for adding vertical structure to planted tanks without overwhelming smaller aquariums.

Lobelia cardinalis at Smith’s Aquatics

At Smith’s Aquatics in Stockton-on-Tees we regularly stock a variety of live aquarium plants, including Lobelia cardinalis.

Our team can help you with:

  • Choosing suitable plants for your aquarium

  • Advice on lighting and plant nutrition

  • Selecting plants compatible with your fish and setup

  • Creating balanced planted aquariums

Visit our store to explore our current selection of live aquarium plants and find the right species for your aquarium.