Floating pennywort (Hydrocotyle ranunculoides) - Non-native Species

Floating pennywort
(Photo credit: Broads Authority)

Floating pennywort is native to North America. It roots in the muddy margins of slow flowing lowland rivers and forms dense interwoven mats. In the UK, these mats have been observed to grow at up to 20cm per day! The species was first found in the wild in Britain in 1990 at a site in Essex. Since then, it has spread rapidly and is proving to be particularly invasive in Norfolk. The plant reproduces principally by asexual, vegetative means and a new plant can grow from a single node; this means that extreme care must be taken when controlling an outbreak of the species. The Broads Authority and Environment Agency are currently taking action to control the spread of this species and eradicate it from certain high priority sites.

Floating pennywort sheet
Management advice