Ludwigia Ovalis

The form of Ludwigia ovalis sold as the pink variety is a stem plant that most people buy for its colour, and the colour is the honest guide to its needs. The oval, opposite leaves run from olive-green to a salmon pink or orange-red depending on light and iron, and the plant only shows its best colour when both are generous.

It comes from East Asia, from China, Japan, Korea and Taiwan, where it grows in slow-moving freshwater. The stems grow upright and fast, and each cutting roots within days, so a few stems become a clump quickly. It does best in soft, slightly acidic water at a pH of 4.5 to 7.

Temperatures of 22 to 26 °C suit it, and it tolerates a wider range in either direction. CO₂ in the 25 to 40 mg per litre range keeps the growth dense and the colour strong; without it the plant grows greener and a little slower. Moderate to strong light completes the picture, and the stems can be grown emersed for propagation.