Economic Importance of Water Lily

The fragrant waterlily, along with other Nymphaea species, is a premier plant for cultivation in containers and ornamental ponds. Most Nymphaea varieties are not difficult to grow. Many hybrids have been developed in hues such as rose, saffron, yellow, purple, and vermilion. The fragrant waterlily and its hybrids is an extremely popular water garden plant and can be readily obtained at nurseries and through mail order catalogs.

Because of its great beauty, northwest property owners have introduced this non-native plant into many Washington lakes; often by transplanting plants from one lake into another. Of 15 lakes surveyed in 1994 in King County, Nymphaea odorata appeared on the species list of all 15 lakes. Shallow lakes are particularly vulnerable to being totally covered by fragrant waterlilies as is 110 acre Giffin Lake in the Sunnyside area of eastern Washington. An aerial photograph of this lake taken in April 1974 shows open water and data indicate that 11-25 percent of the lake was covered by emersed plants (unknown species). Twenty years later, 100 percent of the lake's surface was covered by waterlilies. The photograph shows Chambers Lake in Lacey Washington. This lake has a large population of waterlilies.

Left unmanaged, waterlilies will restrict lake-front access and eliminate swimming opportunities. Requests for waterlily control represent a high percentage of the herbicide permit requests received by Ecology. In several of the integrated aquatic plant management plans funded by Ecology, the fragrant waterlily was considered the second nuisance plant after Eurasian watermilfoil and was targeted for control (Lake Twelve, Steel Lake, Kitsap Lake, Lake Wilderness).