Lobelia (Lobelia cardinalis): decorative and all-terrain plant for aquarium, trashcan garden, and pond
A versatile plant: submerged or emerged
Lobelia cardinalis is an outstanding amphibious plant, capable of growing both underwater and above water. In aquariums, its soft green oval leaves (sometimes reddish depending on conditions) provide an ideal focal point in the foreground or midground. Outdoors, it transforms: tall stems, bushy habit, and especially spectacular bright red flowers from late summer through autumn. It’s truly all-terrain: aquarium, trashcan garden, or pond, it suits all!
Why choose Lobelia?
- Easy to grow in natural or low-tech aquariums (no CO2 addition required).
- Versatile: submerged or emerged, aquarium, trashcan garden, pond.
- Bright red flowering outdoors (wet bank plant).
- Hardy outdoors: withstands the most intense frost (down to approx. −22 °C).
- Easily bushy (new shoots at leaf axils).
- Ideal for creating contrasts of shape and color in aquascaping.
Planting and cultivation tips
- Plant in clumps (several stems) for a strong focal effect.
- Simple substrate (fine or coarse sand) is sufficient. Vigorous roots.
- Medium to strong light: warmer colors (reddish) under intense lighting.
- Pruning and transplanting: take lateral shoots or cut and replant the tops to thicken the planting.
- Outdoors: install on very wet banks or in shallow water. The rootstock is resistant to cold and severe frost.
Possible Uses
- Low-tech aquarium: midground or foreground plant, visual structure.
- Summer trash terrarium: robust growth, easy adaptation, spectacular flowers in late summer.
- Pond and moist banks: tall stems, decorative late flowering.
- Emergent clusters (open tank or paludarium): very aesthetic water/air transition.
FAQ - Lobelia (Lobelia cardinalis)
Is CO2 needed?
No, it grows very well without added CO2 in a well-lit tank.
Can it turn red in an aquarium?
Yes, with strong light and stable conditions, the foliage takes on beautiful reddish hues.
Is it suitable for beginners?
Perfectly: steady growth, easy maintenance, simple trimming.
Can it be used in an outdoor pond?
Yes. In a moist bank, it grows tall and blooms bright red in late summer. It is frost-resistant and stays outside in winter.
How to propagate it?
By cuttings (cut and replant the stems) and by allowing the axillary shoots to bush out.
Additional information
- Scientific name: Lobelia cardinalis
- Plant type: amphibious aquatic plant, hardy in our climates.
- Light: strong light to achieve a beautiful reddish tint, but moderate light is sufficient otherwise.
- Temperature: -22 to 28°C. It is not sensitive to cold or heat.
- Size: up to 1 meter tall in a pond, less in an aquarium (15 to 40 cm).
- Packaging: 1 rooted plant (approximate weight: 10 g).
- Guarantee: without rock wool or any artificial substrate of any kind.
- Recommendation: As a precaution, please never release this plant into the wild. Even though it is present in our regions, we must protect our fragile aquatic ecosystems.
