Curly Leaf Pondweed, Potamogeton crispus

Scientific Name: Potamogeton crispus
Common Name(s): Curly Leaf Pondweed

INVASIVE to MAINE                         Images to come.

Research Summary
: Owen R.
During research for Potamogeton crispus there were things that were difficult.  It was hard to find resources with different information after the first two or three websites and there were some sites that disagreed with each other. For example, one site said this species was not in Maine but all the other ones said it was.  Researching the P. crispus became easy about half-way through the process because I knew which resources were good and which ones were not. It was fun using all the technology during the research.  One of the most important thing I learned while researching my species was that it actually helps stabilize the water quality.  The most surprising thing I learned about my species was that it produces 2.7 million seeds each year.

Identifying Characteristics

  • Submersed leaves only.
  • Stipules ( a small leaf-like appendage typically in pairs at the base of the leaf stalk) joined to the steam at the leaf base measuring 4-10 cm long
  • Leaves are reddish-green oblong and about 3 in long, with distinct wavy edges that are finely toothed.
  • The stem is flat reddish-brown and grows from 1-3 feet long.
  • Measuring 7 cm in length.
  • Arranged in three to five whorls per spike.
  • It can produce 2.7 million seeds each year
  • Turions ( a wintering bud that becomes detached and remains dormant at the bottom of the water) typically measure 1-2 cm long.

Taxonomy of Species
   Scientific Classification
 What That Classification Means
 Kingdom  Plantae  Eukaryotic, many celled, don't move, members make their own food.
 Phylum  Magnoliophyta  Comprising flowers plants that produce seeds enclosed in and ovary.
 Class  Liliopsida  Comprising seed plants that produce an embryo with a single cotyledon
 and parallel-veined leaves.
 Order  Alismatales  An order of flowering plants.
 Family  Potamogetonaceae  Plants that grow in ponds and slow streams.
 Genus  Potamogeton   Pondweed.
 Species  Crispus  Curly pondweed, curly-leaved pondweed.

Similar species include: Clasping-leaf pondweeds, large-leaf pondweed, red pondweed, variable pondweed, and white-stem

Location and Movement
Origin/ Native Range
 Europe and Asia.  
  • Was accidentally introduced to the U.S. waters in the mid 1880's by hobbyists who used it as an aquarium plant.
  • Was originally planted in Michigan lakes as a food source for ducks.
Spread of Species
  • Spreads through winter buds, which are moved among waterways. 
  • They can also reproduce by seed.
  • It attaches to boats and people don't clean off their boats and then they go to a different waters and it spreads.  Turions and plant fragments can be carried on boats, trailers, motors.
Where is it now invasive?  Nearly worldwide, widespread in temperate North America.

Is this species in Maine?
Where has it been identified?
 Was confirmed in a small pond (name not given in resource) in southwestern Maine in 2004.  

How was this species introduced?
 Does not say but was most likely spread to Maine from being attached to a boat.

Natural Environment
  • Lives in fresh water such as lakes, and ponds. 
  • Likes shallow to deep still or flowing water. 
  • Found in alkaline (having a pH value greater then 7) and high nutrients waters. 
  • Prefers soft underwater soils.
Climate and Temperature Range
 It tolerates low light and low water temperatures has been found growing in inches of snow.

Ecological Interactions  Producer.
 It uses carbon dioxide and water in the process of photosynthesis to create sugars for energy.
Consumed By
 Ducks and grass carp.

  • They are responsible for replenishing detritus (particulate matter produced by or remaining after the wearing away or disintegration of a substance or tissue)  that rests on the bottom of the lake.
  • Can be an important primary producer within the habitat that it lives.
  • Impacts the aquatic food web in a lake by blocking out vital light needed for native species to grow.
  • Property values, tourism, fishing and recreational uses are all impacted negatively. 
  • Dense mats form at the surface creating a unpleasant view and odors from decomposing vegetation washed upon shore.
Benefits Helps improve water quality by stabilizing sediment.  

Biological  Grass Carp consumes curly leaf pondweed but is not enough to get rid of this species.
Mechanical/Manual  Harvesting by cutting curly leaf pondweed 5 feet below the surface of the water. 
  • Clean all vegetation of boats and equipment before leaving water access. 
  • Stop turion production.  Deplete seed bank.
 Chemical  There are small number of aquatic herbicides that can be used to control curly leaf pondweed
 such as endothol compounds and Fluridone.

Interesting Facts
  • It is now illegal to sell, or introduce Curly-Leaf Pondweed in Maine