Non-native waterlilies (Nymphaea spp.)


Description:

Appearance: Perennial aquatic herbaceous plant.

Leaves: Floating or slightly emersed in shallow water. Round with "v-shaped" opening or cleft.

Flowers: Unlike native waterlilies which have white flowers (Nymphaea odorata) or yellow flowers (Nuphar variegatum), most exotic waterlilies have brightly colored flowers including pink, purple, and red. Exotics may also have white or yellow flowers and can be difficult to distinguish from native species. Individual flowers have numerous petals and may bloom all summer.

Seeds: Hybrid species may or may not produce viable seeds.

Roots: Fleshy, buried rhizome that can spread extensively..

Ecological Threat:

  • Non-native waterlilies may invade ponds and lakes.
  • Hardy species may expand and choke out native plants.
  • Non-native waterlilies are legally sold as water garden plants but are occasionally illegally planted in public waters.
  • Non-native waterlilies sold for water gardening may also contain "hitchhiker" exotics like harmful exotic submerged plants or zebra mussels. Therefore, even though some exotic waterlilies do not survive Minnesota winters, the more harmful "hitchhiker" exotics can be introduced to our lakes when nursery or mail order species are planted.

This plant is a regulated exotic species in Minnesota and is legal to purchase and possess, but may not be introduced into a free-living state, including public waters or other sites where the species is beyond the control of a person.

 

Control Methods:

A permit is required to work in public waters

Mechanical
Small populations can be removed by digging. Entire underground tuber must be removed. Tubers that are not removed from the water may drift to a new location and regrow

Hand dig isolated plants with care, root fragments can spread and sprout
 

Chemical
Non-native waterlilies are susceptible to control by aquatic herbicides. However, to date, the DNR has not attempted herbicide control of these exotics because they grow in close proximity to native waterlilies which would also be damaged by any herbicide application

Biological
None


Native Substitutes: