Acorus calamus

Acorus calamus has been cultivated across Europe and Asia for millennia for its aromatic properties — the rhizome contains calamus oil long used in traditional medicine and perfumery. In aquatic settings it grows as an emergent plant with long, upright, slightly wavy leaves that can reach 150 cm above the waterline. In the aquarium or paludarium it is strictly a marginal species, with its rhizome at the waterline or just below in shallow substrate. It is cold-hardy and dies back in winter, regrowing strongly each spring.

Light: Medium to high; requires good light above the water surface for strong emergent growth. CO2: Not required; grows as an emergent with leaves mostly above water. Planting: Plant horizontally in shallow substrate at the waterline; the rhizome should be partially exposed. Maintenance: Cut back leaves in autumn when they yellow; divide rhizomes every 2–3 years to prevent overcrowding. Note: Not suitable for fully submerged setups — this is exclusively a marginal/emergent plant.