Limnophila Aromatica

Most plants sold as Limnophila aromatica are something else. What the hobby usually means is Limnophila hippuridoides from the Malayan peninsula, a stem plant with six to eight leaves per whorl that goes deep red under strong light. The true L. aromatica carries two or three leaves per node, occasionally four, and is much less common in tanks. A light green form imported from Taiwan with three to eight leaves per node was once described as Limnophila aromaticoides, now treated as a synonym of this species.

The species name comes from the smell. Crushed leaves give off essential oils, limonene most of all, and across Southeast Asia the plant is a kitchen herb before it is an aquarium subject. It grows as a weed in flooded rice paddies, is used as a spicy herb, and in Vietnam as the base of a herbal infusion. Bunches sold fresh in Asian grocery shops in Europe can be grown submersed, and those plants tend to have wider leaves in whorls of three.

It is a medium-difficulty background stem plant with fast growth, an optimum temperature of 22 to 27 °C and pH 6 to 7.5, carbonate hardness from 2 to 12 dKH, and a tolerance band that stretches from 15 up to 30. Its requirement list puts CO2 fertilisation next to strong light and a steady supply of nitrate, phosphate and micronutrients, in the substrate as well as the water, so plan on CO2 injection. Propagation is by cuttings. It grows emersed in a wet, rich substrate under humid air, flowering in the leaf axils below the shoot tip.