Cuba Ludwigia

One thing is worth knowing before planting Ludwigia inclinata var. verticillata 'Cuba': it does not take trimming well. Cut a shoot off and the rest of the stem may turn black and die, so the working practice is to replant the cutting and treat the old stem as expendable. The plant grows both above and below water in swampy ground on the Isle of Youth off the south-western coast of Cuba, and Flowgrow records the locality as Isla de Juventud, near Cayo Piedra. Tropica brought it into the hobby, at first under the name Ludwigia sp. 'Cuba'. Emersed leaves are green and ovate; submersed they grow long and thin and take on a marbled red and orange pattern. Given light of roughly 0.5 to 1 watt per litre, balanced feeding and room to spread, it grows fast and branches heavily, to the point where it can crowd out a small tank. Nitrate near 5 to 15 mg/l and phosphate near 1 to 2 mg/l support the colour, and whitish new shoots are the sign that iron has run short. CO2 is worth adding: without it the plant makes fewer, wider, greener leaves and slows down considerably. Flowgrow gives an optimum temperature of 24 to 28 °C, a pH of 4.5 to 7, and rates the plant medium in difficulty. Every member of Ludwigia inclinata carries the same large yellow flower whatever its leaf shape and wherever it grows. Propagation is by cuttings, which suits a plant that has to be replanted after every trim.