Bacopa caroliniana

Bacopa caroliniana is native to the wetlands, swamps, and slow-moving waterways of North and Central America, where it grows both submerged and as an emergent plant along shorelines. In the wild it tolerates a wide range of conditions, from brackish marshes to clear freshwater streams, giving it exceptional hardiness in captivity. Its oval, light-green to blue-green leaves are arranged in opposite pairs along erect stems that can reach up to 40 cm tall, making it ideal as a midground-to-background accent. In the aquarium it is prized for its steady, manageable growth rate that does not overwhelm a layout. Under high light the leaves can develop golden-bronze edges, adding color contrast. It is one of the few stem plants that tolerates low CO2 and low-tech setups, thriving without injection as long as macro- and micronutrient levels are adequate. Bacopa caroliniana works beautifully in Dutch-style arrangements as a mid-layer column, in nature aquariums as a background accent behind stones, and in community tanks where its dense stems provide excellent cover for fry and small fish.

Placement Plant in the mid-to-background zone in groups of 5–7 stems spaced 2–3 cm apart to create a full, lush column of green. Its upright habit suits corners and rear walls equally well.

Lighting Backlighting with medium intensity (30–50 PAR at substrate) is sufficient for healthy, compact growth. Under high light (>60 PAR) stems stay shorter and may develop golden highlights. Very low light causes etiolation and leaf drop.

CO2 & Fertilisation CO2 injection is not required but accelerates growth and improves leaf coloration. A full liquid fertiliser providing NO3, PO4, K, and trace elements weekly is sufficient. Increase iron dosing slightly to maintain vivid green colour. In low-tech tanks, root tabs under the stems provide additional nutrients.

Propagation Snip side shoots at 5–10 cm and replant directly into the substrate. The plant also self-branches after trimming, producing multiple new shoots from each cut node. Cuttings root within 7–10 days at recommended temperatures.

Trimming Trim the tops when stems approach the water surface, cutting just above a node pair. Remove lower leaves that have yellowed or are buried in the substrate to prevent rot. Regular trimming every 2–3 weeks keeps the plant bushy and prevents it from shading lower plants.