- Hardiness: Easy
- Light Needs: Medium
- Plant Structure: Stem
- Family: Plantaganaceae
- Genus: Bacopa
- Region: North America
- Location: U.S.A.
- Size: Stem width: 3-6cm (1-2in)
- Growth Rate: Moderate
- Can Be Grown Emersed: Yes
Bacopa caroliniana has been a ubiquitous species within the aquatic plant hobby for many years and is commonly available as a regular offering of both brick-and-mortar and internet retailers. Several forms of this species are currently in culture, including a small-leaved form and a variegated form (the latter of which seems to be of only limited contrast to the standard form, however). One of the most characteristic traits of this plant is the lemony smell exuded by its leaves when they are crushed. Bacopa caroliniana is native to the southern U.S., where it can be found growing in marshy areas in both emersed and submersed states.
This relatively slow-growing stem plant's primary requirement in the aquarium is sufficient light, which at the lowest should be maintained at 2 watts per gallon. Fertilization with both macro- and micronutrients is unnecessary but productive, as is supplemental carbon dioxide injection. If lighting is intense and nitrates are low, this plant will turn a dull copper or brownish color. When phosphates are limited, it will attain a pink blush. Emersed culture outdoors on the edge of a pond or in a well-lit tub will produce good growth and the characteristic purplish flowers of this species. B. caroliniana is an excellent candidate for non-CO2 aquaria.
Propagating Bacopa caroliniana is easy, since the bottom portions of any severed or 'topped' shoots easily develop new growth tips. It also regularly produces runners at the base of the stem, which can be carefully trimmed and replanted.
The stems of Bacopa caroliniana are most effectively employed in the aquascape if they are placed in a terraced or tiered grouping in the middle or front area of the aquarium, where their unique geometry constitutes a stable point upon which other plant groupings can be based.