Yellow flowers are produced on stems up to 1.2m in mid May. Pollinated by many insects, it sets large seed pods. It absorbs a good amount of nitrogen to produce strap-like leaves, helping to keep the water free of algae and then shading it to keep it cool. Dragonfly larvae are often to be found on leaf undersides in the process of hatching.
Sow at any time, but benefits from a period in the fridge mixed with damp sand for a a few weeks before sowing in a good quality seed compost, 2 or 3cm deep.
Needs to be planted in damp soil or at the waters edge and will produce more flowers if placed in full sun.
Seed from Shropshire