Best time to see: May to end Aug

Key facts

Once a popular pond plant, it produces large floating mats of feathery leaves that soon dominate ponds and lakes

Thin feathery leaves in whorls on sticky stems extend up to 45cm above the water; tiny white flowers in summer

Can be confused with water-milfoils but these have no leaves above water; banned from UK sale in 2014

Extras

Most stems are above water, in large patches, 15–45 cm high; sticky (if you can reach it!)

Flowers are tiny white stars in whorls, but only on some stems and hard to spot.

Leaves are feathery, thin, in whorls on the stems