TankBud

One species · 2 forms

Lobelia cardinalis

Also known as Cardinal flower, Cardinal plant

FreshwaterStemSide shootsCuttings

Care at a glance

Light
Medium light
CO2
No CO₂ needed
Temperature
64–79°F
18–26°C
Max height
11.8 in
30 cm
Growth rate
Medium
Placement
Midground
Type
Stem
pH
6.0–7.5
Hardness
4–15 dGH
Spread
3.9 in (10 cm)
Nutrient uptake
Root + water column
Growth region
Submersed or emersed
Difficulty
Easy
Family
Campanulaceae
Origin
North America (eastern USA, Canada, Mexico, Central America)

Pick a form

Mini and Wavy take the same care as the species, with medium light and no CO2 needed.

Overview

Lobelia cardinalis is an easy stem plant for the midground of the tank.

Did you know

Lobelia cardinalis looks like two different plants above and below water. Emersed, it makes broad, pointed green-to-bronze leaves, while its submersed leaves are narrower, fleshier and light green. A freshly converted plant can look like a different species for a few weeks.

Caring for Lobelia cardinalis

Plant individual stems of Lobelia cardinalis in the midground, a little apart. It forms tidy bushes rather than tall stems, so it also works as a foreground-to-midground accent.

It does fine in medium light without CO2. Good light, CO2 and regular dosing keep it more compact and a brighter fresh green. It feeds through roots and leaves, so root tabs and a liquid fertilizer cover both.

It grows at a moderate pace and needs little trimming. Trim the tops to keep it dense and replant them, or cut side shoots off once they have a few leaves. It grows at 64 to 79°F (18 to 26°C).

Lobelia cardinalis Mini arose as a mutation in Tropica's own Lobelia cardinalis nursery stock. Tropica puts it at 3 to 15 cm, against 20 to 30 cm for the species, with round leaves set close on the stem. Wavy is a selection with wavy, pale green, spoon-shaped leaves, and Aquasabi puts it at about 15 cm.

Mini belongs in the foreground, where it stays a low cushion. Wavy sits in the midground with the species.

Good to know

Lobelia cardinalis belongs to the bellflower family, Campanulaceae, in the subfamily Lobelioideae. It is not a true aquatic but a marsh plant that adapts to permanent submersion. Its brilliant scarlet flowers are pollinated by hummingbirds in its native range. The compact 'Mini' cultivar sold for aquascaping is a dwarf selection, much shorter and bushier than the wild type.

In the wild

Lobelia cardinalis is native to wet meadows, stream banks and marshy ground across North America. Its range runs from the eastern United States and southern Canada down through Mexico into Central America. In the wild it grows emersed as a bog plant, and the aquarium form is the same species kept underwater.

Common questions

Which Lobelia cardinalis suits the foreground?

Lobelia cardinalis Mini. Tropica rates it at 3 to 15 cm, while the species and Wavy grow taller and belong in the midground.

Does Lobelia cardinalis need to be planted in the substrate?

Yes. Strip the leaves from the lower part of each stem, then push the stems into the substrate one at a time, a little apart.

Does Lobelia cardinalis need CO2?

No. Lobelia cardinalis grows well without added CO2.

How much light does Lobelia cardinalis need?

Lobelia cardinalis wants medium light. A light sold for planted tanks covers it.

Does Lobelia cardinalis need root tabs?

They help. Lobelia cardinalis takes nutrients through both its roots and its leaves. Root tabs near its roots and a liquid fertilizer cover both.

How do you propagate Lobelia cardinalis?

Lobelia cardinalis propagates by side shoots and cuttings. Cut a side shoot off once it has a few leaves and plant it on its own. Cut off the top of a stem and replant it, and the stump left behind grows new shoots.

How tall does Lobelia cardinalis grow?

Lobelia cardinalis grows to about 11.8 in (30 cm) tall. It grows at a moderate pace.

Related plants