Alisma plantago-aquatica L.
Alisma plantago-aquatica, commonly known as Water Plantain, is an "amphibian" perennial, a marsh plant or a rooting aquatic plant.
Alisma plantago-aquatica was described in 1753 by Carl von LinnÃ©. The name is considered validly published. The epithet very likely refers to the "Plantain-(Plantago)like leaves.
Water Plantains grow in loose upright clumps and reach heights of 40 to 80 centimetres with a spread of 30 to 50 centimetres. The towering and protruding inflorescences form the highest part of the plants.
Alisma plantago-aquatica is a decidious plant with long-petiolate, simple and basal leaves. The linear-lanceolate to broadly elliptic or ovate leaves are midgreen and up to 25 centimetres long. They are up to 10 centimetres wide with reticulate venation and entire margins. The leaf base is rounded or slightly cordate. Plants in running water may form strap-formed submersed and emersed leaves.
Flowers and Fruit
The three-petaled flowers are white to pale pink and appear from June to August. They are arranged in leafless, upright pyramidal inflorescences that are up to 1 metre high and made up of panicles. The pedicels are 1 to 3,5 centimetres long, the flowers have a diameter of 6 to 10 millimetres.
The fruits are nutlets made up of ovate achenes that are 1,7 to 3,1 millimetres long. The seed ripen from July to October. The nutlets disintegrate into numerous small fruits with a floating tissue that may keep them floating for up to 15 months. The seeds need cold temperatures for germination.
A bulbous rootstock partly produces long, few-branched roots.
Alisma plantago-aquatica is native to the whole of Europe, Turkey, the Eastern Mediterranean, the Caucasus, Iran, west Sibiria, Afghanistan and Pakistan.
The perennials are aquatic plants and prefer a sunny situation. They prefer soil with a pH between 6,3 and 7,5 and need a soil depth of at least 41 centimetres for good growth. They tolerate temperatures down to -23Â°C (USDA zone 6) and need a frost-free period of at least 16 weeks. The plants are suited for the shore areas of and in artificial standing bodies of water, the shores areas of and in natural standing bodies of water, natural streams, shallow water and bog gardens, the planting depth is at 30 centimetres. It is usually found in shallow zones of lakes and rivers, especially on wet banks used for pasture, in ditches and ponds or fertile pools, rarely in poor waters.
Classification after Prof. Dr. Sieber
Tolerance of special soil conditions
- none: soil salinity, drought
- medium: calcareous soil
- high: anaerobic soil
A sunny position in shallow water promoted rich bloom.
Well suited for small and large water surfaces with fertile soil. Also a good agricultural plant for clarifying and repositioning. The plants are best planted at a water depth of 5 to 40 centimetres with 3 to 5 specimens per mÂ².
Alisma plantago-aquatica is also used medicinally, as specimen plant and as cut flowers.
Maintenance and Propagation
The plants need little to no maintenance if grown under suitable conditions.
- Cut back before seeds ripen to prevent self-seeding.
The plants self-seed freely so that deadheading is recommended in garden ponds. Withered inflorescences make good cut flowers.
Propagate by dividing the rootstock in May/June.
Varities and Cultivars
- Alisma triviale (A. pantago-aquatica subsp. brevipes) - Northern water plantain
- Alisma plantago-aquatica subsp. orientale
All parts of the plant contain a milky sap that irritates the skin. In addition the roots contain a bittern and an essential oil. They smell like Iris but are toxic. The plants are supposed to be leathal to grazing cattle. The toxic agents degrade when the plants are dried.
Please read the health issues note!
Pests and Diseases
If the plants are infested with rust they should be cut down sharply and the leaves should be destroyed. Remove leaves in autumn at the latest to avoid rust infection in spring.
Aphids may occasionally occur but should simply be ignored since fish and other aquatic animals are very sensitive to insecticides.
- Walter Erhardt, Erich GÃ¶tz, Nils BÃ¶deker, Siegmund Seybold: Der groÃe Zander. Eugen Ulmer KG, Stuttgart 2008, ISBN 978-3-8001-5406-7. (Ger.)
- Christoper Brickell (Editor-in-chief): RHS A-Z Encyclopedia of Garden Plants. Third edition. Dorling Kindersley, London 2003, ISBN 0-7513-3738-2.