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Montana Field Guide

Montana Field Guides

American Water-lily - Nymphaea odorata
Other Names:  Fragrant Water-lily, American White Water-lily

Aquatic Invasive Species
Non-native Species

Global Rank: G5
State Rank: SNA
(see State Rank Reason below)

Agency Status
MNPS Threat Rank:
C-value: 0

External Links

State Rank Reason (see State Rank above)
Nymphaea odorata is exotic in Montana (FNA 1997; Booth and Wright 1966), but is not listed as a noxious weed in Montana. Plants in Montana are subspecies odorata (FNA 1997; Lesica 2012). It was introduced from the eastern United States for its ornamental appeal (FNA 1997; Lesica 2012). In some states and provinces Fragrant Water-lily is considered invasive. A conservation status rank is not applicable (SNA) because exotic plants are not a suitable target for conservation activities.
General Description
PLANTS: Aquatic perennials with floating leaves and floating, showy flowers (Lesica 2012). Rhizomes are 2-3 cm in diameter, long, branched, creeping, and covered with short, black hairs (DiTomaso and Healy 2003).

LEAVES: Large, floating, nearly orbicular, and 8-20 cm long (Lesica 2012). Leaves are green above and green to purple below (FNA 1997). Margins are entire (smooth) and bases are cordate-shaped, like the top of a heart (FNA 1997). Petioles are long and attached to a rhizome.

INFLORESCENCE: Singular flowers have at least 17 white, showy petals, 4 green or reddened sepals of at least 3 cm long, and float with long peduncles (flower stems) (FNA 1997; Lesica 2012).

Flowering occurs from spring to summer, or into early fall for more southern populations (DiTomaso and Healy 2003).

Diagnostic Characteristics
In Montana three genera represent the “water-lily family”: Brasenia (water shield), Nuphar (pond-lily), and Nymphaea (water-lily).

Brasenia spp. have round to elliptical floating leaves with no basal sinus or split in the leaf.

Nuphar spp. have heart-shaped floating leaves (appear split), yellowish sepals, and inconspicuous petals.

Nymphaea spp. have heart-shaped floating leaves (appear split), 4 green sepals, and numerous white petals. In Montana Nymphaea odorata and N. leibergii differ in their fragrance, sepal length, and number of petals. Nymphaea odorata has fragrant flowers (Hitchcock et al. 1964), at least 17 white petals, and sepals of at least 3 cm long (Lesica 2012). Nymphaea leibergii lacks fragrant flowers (Hitchcock et al. 1964), has 7 to 15 petals, and sepals of 3 or less cm long (Lesica 2012).

In Montana our plants are Nymphaea odorata subspecies odorata.

Species Range

Range Comments
Introduced from the eastern United States, Fragrant Water-lily is found in all western states except Wyoming (DiTomaso and Healy 2003). Two subspecies (tuberosa and odorata) are recognized in the United States, and where populations overlap intermediate forms develop (FNA 1997).

For maps and other distributional information on non-native species see:
Nonindigenous Aquatic Species Database from the U.S. Geological Survey
Invasive Species Habitat Tool (INHABIT) from the U.S. Geological Survey
Invasive Species Compendium from the Centre for Agriculture and Bioscience International (CABI)
EDDMapS Species Information EDDMapS Species Information

Observations in Montana Natural Heritage Program Database
Number of Observations: 288

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density



(Observations spanning multiple months or years are excluded from time charts)

Acidic to alkaline lakes and ponds in valleys (DiTomaso and Healy 2003; Lesica 2012).

Ecological Systems Associated with this Species
  • Commonly Associated with these Ecological Systems
    Wetland and Riparian Systems

Fragrant Water-lily has rhizomes that can tolerate some desiccation (DiTomaso and Healy 2003). Plants can also become abundant, shading out native plants,and impairing recreation.

The following animal species have been reported as pollinators of this plant species or its genus where their geographic ranges overlap: Bombus vagans (Colla and Dumesh 2010).


  • Literature Cited AboveLegend:   View Online Publication
    • Colla, S.R. and S. Dumesh. 2010. The bumble bees of southern Ontario: notes on natural history and distribution. Journal of the Entomological Society of Ontario 141: 39-68.
    • Flora of North America Editorial Committee. 1997. Flora of North America North of Mexico. Volume 3. Magnoliophyta: Magnoliidae and Hamamelidae. Oxford University Press, Inc., New York, NY. xxiii + 590 pp.
  • Additional ReferencesLegend:   View Online Publication
    Do you know of a citation we're missing?
    • Booth, W. E. and J. C. Wright. 1966. Flora of Montana-Part II: dicotyledons. Montana State University, Bozeman, MT. 305 pp.
    • DiTomaso, J.M. and E.A. Healy. 2003. Aquatic and riparian weeds of the West. Regents of University of California, Division of Agriculture and Natural Resources, Publication 3421.
    • Hitchcock, C. L., A. Cronquist, M. Ownbey, and J. W. Thompson. 1964. Vascular Plants of the Pacific Northwest. Part 2: Salicaceae to Saxifragaceae. University of Washington Press, Seattle. 597 pp.
    • Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
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Citation for data on this website:
American Water-lily — Nymphaea odorata.  Montana Field Guide.  .  Retrieved on , from