Cuba Mermaid Weed

Proserpinaca palustris 'Cuba' is the Cuban form of mermaid weed, the strain that reaches European aquarists almost exclusively. The species itself is native to the eastern United States, the Caribbean, and parts of Central and South America; the cultivar sold under this name was found on the Isla de la Juventud, off the coast of Cuba. Flowgrow notes that the Cuban variety seems to differ from its North American relatives and that European trade probably carries only this form, so nearly every mermaid weed in Europe is this Cuban strain. Young plants carry saw-toothed leaves; once settled in the tank the leaves change to long, finely toothed, needle-like blades. Under strong light the plant takes on a copper colour. It grows as a stem plant about 10 to 40 cm tall and 5 to 10 cm wide, best placed in the midground or background of a smaller aquarium. Care matches the species: strong light, an optimum temperature of 20 to 25 °C, slightly acidic water around pH 5 to 7.5, and steady feeding with low nitrate to keep the red. CO2 is helpful but not essential.