Alisma plantago-aquatica (common water-plantain)

Flower of Alisma plantago-aquatica (Image: Wolfgang Stuppy)

Common water-plantain is a widespread temperate species occurring across Eurasia and from North Africa to Tanzania. It is also considered to be native in parts of Australia.

It is widely cultivated and has been introduced and become naturalised in parts of North and South America, Australia and New Zealand.

Alisma plantago-aquatica subspecies orientale is native to eastern and central Asia.

Illustration of Alisma plantago-aquatica (Image: Prof. Otto Wilhelm Thomé, Flora von Deutschland, Österreich und der Schweiz, 1885)

Overview: An aquatic or semi-aquatic perennial with a clumped habit, up to 1 m tall.

Leaves: Rosettes of grey-green, elliptic, ribbed leaves, rounded at the base, up to 30 cm long on long fleshy stems.

Flowers: Tall open panicles of white flowers, sometimes with a pink or pale lilac tinge, up to 15 mm in diameter. Petals and sepals are in threes; there are six stamens (male parts) and numerous (variable) stigmas/carpels (female parts).

Fruits: Made up of a cluster of numerous achenes (dry fruits containing one seed) up to 7 mm in diameter. The fruits are buoyant, allowing water-borne dispersal.

Seeds: Deep reddish-brown to light pink or yellow. Remaining viable in water for many years.

Flowering stems emerge from the centre of the leaf bases, and delicate white, pink or lilac flowers unfurl in the afternoon for only a few hours, before closing again at dusk. During this time, the flowers are pollinated by flies, which are attracted by small drops of nectar.

The rhizome (underground horizontal stem) is used as a diuretic, but prolonged use may cause gastroenteritis (inflammation of the stomach and intestines).

According to the Flora of Pakistan, the powdered root has been used as a cure for hydrophobia, and fresh leaves are used in homeopathy. The starch-rich rootstock is also eaten in some countries.

John Ruskin, the well-known Victorian art critic, believed that the curve of this plant’s leaves was representative of ‘divine proportion’, and advocated the emulation of nature and natural forms such as this in architecture, as in the Gothic style.

Seeds of Alisma plantago-aquatica (Image: Wolfgang Stuppy)

The Millennium Seed Bank Partnership aims to save plant life worldwide, focusing on plants under threat and those of most use in the future. Seeds are dried, packaged and stored at a sub-zero temperature in our seed bank vault.

Twelve collections of Alisma plantago-aquatica seeds are held in Kew’s Millennium Seed Bank based at Wakehurst in West Sussex.

See Kew’s Seed Information Database for further information on Alisma plantago-aquatica seeds.

Common water-plantain makes a good marginal or emergent plant for a wildlife garden or around lakes or garden ponds. It performs best in full sun and can grow in any aspect, in an exposed or sheltered site. It can be planted in up to 30 cm of water.

It can be propagated from ripe seed, freshly sown, or by dividing the rhizomes in spring. It will reach full height within 2–5 years.

Alisma plantago-aquatica in Kew’s Aquatic Garden (Image: Alice Lumb)

Alisma plantago-aquatica was first recorded in cultivation at Kew in 1768. It was first recorded growing wild in its natural habitat in the Gardens in 1873.

In recent years, it has been found growing wild in the ditch alongside the towpath, in one spot beside the Lake, and in the Larch Pond in the Conservation Area. It has been planted near the Sir Joseph Banks Building and can also be seen in cultivation in the Aquatic Garden, next to the Grass Garden. It can also be found growing at Wakehurst Place, Kew’s sister garden.

Dried specimens of Alisma plantago-aquatica are held in Kew’s Herbarium, where they are available to researchers by appointment.

Specimens of root and tubers of common water-plantain, used in medicine, are held in Kew’s Economic Botany Collection, where they are available to researchers by appointment.

Search Kew’s science databases for more information on Alisma plantago-aquatica

Visit the BSBI (Botanical Society of the British Isles) website for a map showing the distribution of Alisma plantago-aquatica across Great Britain and Ireland, from the 1930’s to the present day.

To see herbarium specimens of Alisma plantago-aquatica online visit the collection at the Royal Botanic Garden Edinburgh

eMonocot - an online resource for monocot plants