IF you want a terrific bog plant which provides vibrant yellow flowers above dark green rounded leaves, look no further than the caltha.

If you want to provide impact in a sunny spot near your pond, plant this one in drifts or groups in early spring. Deadhead when the daisy-like flower is past its best and remove any leaves that look tatty.

For the best choice of calthas, visit an aquatic centre or pond-plant specialist. Good varieties include C. palustris radicans Flore Pleno, a double-flowered type, or C. palustris Palustris, more commonly known as the giant marigold, which grows to 30in (75cm) and produces big yellow flowers.