Lobelia cardinalis

Overview: One of the versatile aquatic plants, Lobelia cardinalis, also popularly known as the Cardinal plant, is native to North America. It can be grown in submerged as well as emersed conditions; thus, it is suitable for aquariums, terrariums, and palludariums. The slow-growing habit of Lobelia cardinalis makes it perfect for planting as a foreground plant. Regular trimming can form a beautiful mat-like formation, giving a reddish-purple mat in your tank.

Appearance: The beautiful cardinal plant has dark green round-shaped leaves with a tinge of reddish purple to brown color on the top. The red-purple coloration is more popular when the plant stays completely immersed in water, that is, in aquariums. At the same time, Lobelia cardinalis can also develop bright red flowers under this condition, giving a stunning contrast to the aquarium. Due to its small height (10 – 30 cm) and slow growth pattern, the cardinal plant looks great when used as a foreground or mid-ground plant. However, if it turns red, placing it as a background plant also works equally well. 

Hard/Soft Plant: It is a hardy plant with a compact growth form.

Ideal water temperature: For the best growth, maintain the temperature around 17° - 28° C as it will help the cardinal plant to show its true colors and best growth. 

Lightening Conditions: The plant requires moderate to high light conditions to show optimum growth. Under low light conditions, the plant stays stunted and does not thrive for longer.

Ideal pH level: pH should remain between 6 to 7. 

Other requirements: A nutrient-rich substrate works well for cardinal plants to thrive well in the tank and give out the best colors. At the same time, additional carbon dioxide will help to maintain its optimum growth; however, it is not a necessity. 

Propagation: Lobelia cardinalis is a stem plant that shoots out new branches readily. While pruning or trimming the plant, make a cut just above the internode and replant it to generate its siblings. The rooted portion generates new shoots with no hassle and grows bushy over days. 

Do you know: Due to the slow growth and small height, the cardinal plant is often used as a foreground plant; however, with regular trimming, it can be used to give a mat-like appearance. The side shoots need to be maintained properly for the best results.