Limnophila Hippuridoides

Count the leaves at a node and you will know what you bought. Following Kasselmann's 2010 account, this marshweed is told from its relatives that way: Limnophila hippuridoides carries 6 to 8 leaves per node and colours reddish to dark red, L. aromatica has 2 or 3 of variable colour, and L. aromaticoides has 3 to 8 and stays light green. The plant has been traded under both of those names, under the misspelling L. hippuroides, and even as Gratiola officinalis, which is a different species altogether. It comes from the Malay peninsula.

Light is the first thing to get right, but the nutrient and carbon dioxide side should not be underestimated either: injected CO2 together with adequate nitrate, phosphate and trace elements is necessary. Iron matters most for colour. A nutrient-rich substrate speeds the plant up, because it roots heavily. Colour deepens when nitrate runs low or phosphate runs high, which is the familiar trade-off between growth and red.

Run it at 22 to 27 °C and pH 6 to 7.5, in strong light, at the back of a large tank. Growth is fast, so plan the trimming: cutting the top shoot pushes it into lateral growth, and replanted cuttings need spacing so they do not shade each other out. Left to reach the surface it starts producing emersed leaves. Crushed leaves smell aromatic, as they do in the rest of the group.