Fennel Pondweed - Potamogeton pectinatus


The grass-like Fennel Pondweed is a submerged plant that grows from a creeping rhizome. The multiple long stems often form masses at the water surface. Underwater stands may look like grassy meadows. The stems are slender and flexible. They are only about an eighth of an inch thick and are usually several feet long. The stems have many branches, and may be green, brown, or reddish. Fennel Pondweed leaves are very narrow; not much wider than the slender stems. The leaves are usually several inches long. They taper to narrow points. The flowers of Fennel Pondweed are on spikes. The flowers are very tiny and greenish, and grow in several whorls along the flower spike.

Similar Species

other narrow-leaved pondweeds

Identification difficulty
Recording advice

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Fennel Pondweed grows in fresh, brackish, and saline waters. It is found in ponds, lakes, rivers and canals.

When to see it

Flowers June to September.

Life History


UK Status

Widespread in England, predominantly coastal in Scotland and Wales.

VC55 Status

Fairly frequent in Leicestershire and Rutland. In the 1979 Flora survey of Leicestershire it was found in 67 of the 617 tetrads.

Leicestershire & Rutland Map


Yellow squares = NBN records (all known data)
Coloured circles = NatureSpot records: 2020+ | 2015-2019 | pre-2015

UK Map

Species profile

Common names
Pond weed, Fennel Pondweed
Species group:
Records on NatureSpot:
First record:
18/08/2013 (LLPNHS;Steve Woodward)
Last record:
16/06/2018 (Nicholls, David)

Total records by month

% of records within its species group

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