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, recorded as Isla de Juventud, near Cayo Piedra. It entered 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. Strong light, balanced nutrition, added CO₂ and room to spread support fast, branching growth. In a confined aquarium the developing group can crowd its neighbours. 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. The optimum is 24 to 28 °C at pH 4.5 to 7, and the plant is 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.