Alisma plantago-aquatica

Common Waterplantain

Waterplantain, Alisma plantago-aquatica
Common Waterplantain

Flora, fauna, earth, and sky...
The natural history of the northwoods


  • Alisma, the Latin name for water plantain and ancient Greek name, adopted by Linnaeus from Dioscorides. Perhaps itself derived from the Celtic, alias, "water"
  • plantago-aquatica, from the Latin, plantago, "plantain", and aquatica, "in water"; hence, "water plantain". The name Plantago is a misnomer, applied by early botanists impressed with the similarity of its leaves to those of the plantain, while ignoring the many significant dissimilarities (flower, fruit, etc.).
  • Common name, from the resemblance of the leaf to that of the unrelated, terrestrial plantain, and from its aquatic habitat.
  • Other common names include: American Waterplantain, Great Water-plantain, Marsh Drain, Mad-Dog Weed, Plantain d'eau - Flûteau (Fr), Ratamosarpio (Fin), Svalting, Kranssvalting, Vanlig Svalting (Swe), Chastukha Podorojnikovaya (Rus), Zabieniec babka wodna (Pol), Vassgro (Nor), Vejbred-Skeblad (Dan), Gewöhnlicher Froschlöffel (Ger), Waterweegbree (NL), Corr-chopag (Gaelic)


  • Kingdom Plantae, the Plants
    • Division Magnoliophyta, the Angiosperms (flowering plants)
      • Class Liliopsida, the Monocotyledons
      • Subclass Alismatidae
        • Order Alismatales
          • Family Alismataceae, the water plantains
            • Genus Alisma, water plantain
  • Taxonomic Serial Number: 38894
  • Much controversy surrounds the treatment of Alisma in North America. At present three distinct native species in North America are generally recognized (P. Rubtzoff 1964) as well as the probable occurrence of two introduced species, one in California and the other in Alaska.


  • A perennial aquatic herb, 3'-4'
  • Leaves large, basal, elliptic to ovate, pointed at the tip, rounded or sometimes heart-shaped at the base, up to 8" long. Submerged leaves to 4" long and 2" wide. Smooth in texture, with often wavy margins, and very strongly veined, the mid-rib and about three on either side being quite conspicuous. Leaf stalk long, not branched, but deeply channelled, broadening out and sheathing at their bases. The large leaves all spring directly from the root, growing in a nearly erect position.
  • Stems erect, smooth, obtusely three-cornered, up to 3', bearing only whorls of flowers. Leafless flowering stems extend well above the leaf blades. Flower-bearing branches spring laterally from stem at its upper extremity in whorls, these branches themselves further branched in like fashion, the whole forming a loose pyramidal panicle.
  • Roots thickened fibrous, but the base of the stem is swollen and fleshy, or tuberous and furnished with a tuft of numerous whitish hairs.
  • Flowers borne in whorls on the stem, white, 1/4"-3/8" across, clustered in whorls of 3-10.
    • Sepals 3, green, concave, ovate, rounded tip, to 1/8" long
    • Petals 3, white, free from each other, slightly jagged at their edges, up to 1/12" long
    • Stamens 6, their anthers of a greenish tint
    • Pistils several, in a ring
    • Ovary superior (within blossom)
  • Fruit an achene, borne in circular heads up to 1/6" in diameter; each achene obovate, about 1/8" long, with a minute beak


  • An aquatic plant rooted in the mud of lakes or slow streams, but with the leaves and flowers held above the water.
  • Distinguished from closely related Alisma and Saggitaria species by the shape of the leaf and by the flowering stem which rises well above the height of the leaves.
  • Field Marks
    • Large, plaintain-like leaves in a basal rosette
    • Small, white flowers in clusters on a stout flowering stem


  • Nova Scotia to southern British Columbia; south to Pennsylvania, Missouri, and California. Also Europe and northern Asia.


  • Marsh and shallow waters of lakes and slow moving streams
  • Ditches
  • Wet, boggy soils




  • A weed problem in cultivated rice fields.
  • Fresh leaves and roots are toxic
  • Many and varied medicinal uses attributed to plant including the alleged treatment of rabies, hence the common name "Mad-Dog Weed"


  • Sexually by seed
    • Flowers mid to late summer
    • Seed dispersed on the water, or by waterfowl


  • By seed or rootstock division
  • Will self-sow aggressively in a suitable setting


  • Hardy to USDA Zone 3 (average minimum annual temperature -40ºF)
  • Cultural Requirements
    • Sun full
    • Soil medium to heavy, poor to no drainage
    • Calm or slow moving water to 6"
  • Growth rate fast
  • Good for garden ponds and water gardens, wet soil and marshes
  • One of the first water garden plants to break winter dormancy in early spring
  • Available by mail order from specialty suppliers, especially those catering to the wetland restoration market.



  • A tough, dependable plant for the water garden.

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Last updated on 4 March, 2006