Bacopa caroliniana (Emergent)

Bacopa caroliniana is a North American aquatic plant that thrives in both submerged and emergent conditions. In its emergent state, the stems thicken and the leaves become more succulent and aromatic — crushing a leaf releases a distinctive lemon scent. Small, attractive blue to violet tubular flowers emerge from the leaf axils, adding delicate floral detail to the waterline zone of a paludarium. The stems grow upright with a neat, tidy habit that is easy to manage.

It is one of the most cold-tolerant aquatic stem plants, surviving temperatures as low as 10 °C, which makes it suitable for temperate-themed paludariums as well as tropical builds. The emergent form grows more slowly than the submerged form, giving a longer period before trimming is required. It is an excellent beginner plant for the riparian zone with few demands beyond adequate light and access to water at its roots.

Light: Medium to high; 2,000–5,000 lux; flowers are produced most freely under strong light. CO2/Humidity: No CO2; roots must remain in water or saturated substrate; stems grow in ambient air. Fertilisation: Monthly dilute liquid fertiliser into the water section at the root zone. Placement: Plant in substrate at the waterline; emergent stems grow upward into the air zone naturally. Propagation: Stem cuttings replanted in saturated substrate root within 1–2 weeks.