Bacopa caroliniana

Quick facts

Max height

30 cm

Growth rate

moderate

Difficulty

beginner

Placement

midground, background

Propagation

stem cuttings

Water parameters

Temperature

18–28°C

pH

6.0 to 7.5

Hardness

3 to 20 dGH

Cold water

tolerated (unheated setups)

Light and nutrients

Lighting

medium

CO2

not required, but boosts growth and color

Substrate

inert ok

Feeding

feeds from both water column and roots (liquid ferts plus root tabs)

Substrate

What this plant roots into (or attaches to). The substrate affects both plant nutrition and water chemistry; see each linked page for full effects.

This plant feeds primarily from the water column, so substrate choice matters more for its fish-tank compatibility than for plant nutrition.

With fish

Plant-eating fish

safe with plant-eating fish (tough leaves or unpalatable)

Diggers (corydoras, loaches)

may get uprooted by active diggers

Root-disturbing fish

tolerates fish that disturb roots

Habitat

Native to the southeastern United States, from Texas and Florida north through the Carolinas. Found in marshes, pond margins, slow streams, and wet meadows. The species grows both emersed (above water, with round, succulent leaves) and submerged (with more elongated, thinner leaves). Bacopa caroliniana is one of the few aquarium stem plants native to North America. The leaves are arranged in opposite pairs along a thick, upright stem. Submerged leaves are oval, 1–2 cm long, and medium to bright green. Under strong light, the leaf tips and upper portions develop a copper to bronze tint. The plant has a subtle lemony scent when the leaves are crushed, which is noticeable when handling it during trimming.

Outdoor pond use

This species transitions to outdoor ponds well, not just indoor aquariums.

Outdoor pond zones (USDA)

5 to 11 (winter low around -29°C or warmer)

Below the minimum zone, the plant won't overwinter outdoors but can still be grown seasonally and overwintered indoors. Several pond-friendly species (water hyacinth, water lettuce, parrot's feather) are regulated as noxious in some jurisdictions; check the legality data on the profile before releasing anything to an outdoor body of water.

Care notes

One of the easiest stem plants for beginners. Grows in low to high light, with or without CO2, in soft or hard water. Under low light, growth is slow but healthy; stems stay compact and green. Under high light with CO2, growth accelerates and the tips develop copper to bronze coloring. The thick stems and opposite leaf arrangement give it a structured, orderly appearance compared to more flowing stem plants. Plant stems in groups of 5-8, pushed into the substrate with 2-3 nodes buried. The buried nodes produce roots within days. Trim when stems reach the surface by cutting the top 10–15 cm and replanting the cuttings. The cut lower stems produce side shoots. Growth is moderate; weekly or biweekly trimming keeps a group tidy. Nutrient requirements are moderate. Root tabs help but aren't strictly necessary because Bacopa feeds from both roots and the water column. Not demanding about water chemistry; it grows well in pH 6.0-8.0 and soft to hard water. Propagation by cuttings is reliable and fast. One of the best plants for a first planted tank because it's almost impossible to kill and provides a good learning experience for stem plant management. The plant can also be grown emersed in terrariums, paludariums, and outdoor bog gardens in warm climates. The emersed form has rounder, thicker leaves and can flower with small blue to purple blooms. Transitions between emersed and submerged growth involve a brief adjustment period where old leaves may shed before new growth adapted to the current conditions emerges.

Further reading

• How to cycle a fish tank
• Water chemistry for fishkeepers: pH, GH, KH, and what they mean