curly pondweed, curly-leaved pondweed, curly cabbage, crisp pondweed
Curlyleaf pondweed is another hardy and incredibly invasive submerged aquatic. It has oblong 2 – 3 inch blue-green leaves that are wavy along the edges, like lasagna. Along the edges of the leaves you will find very small serrated edges. Like Eurasian Watermilfoil, the flower stalks stick above the water’s surface and appear reddish-brown in color. This plant produces small greenish brown pine cone look-a-likes called turions. Curlyleaf pondweed forms dense mats in the water, which die off to create a great deal of waste in bodies of water. This plant has an extensive and dense root system and can tolerate extreme conditions.
Curlyleaf pondweed can be distinguished from other pond weeds because its leaves attach to the stem in an alternating pattern and secondary veins branch from a midvein in perpendicular pattern. Native pondweeds have parallel leaf veins.
Like many noxious invaders, curlyleaf pondweed is an incredibly adaptive and hardy plant. It can grow in a variety of different locations and sediment types, and it can tolerate extreme conditions including low light and cold water temperatures and has even been found growing under inches of snow and ice. It can grow in deep or shallow waters and prefers soft soils and sediments. It will also grow well in waters that have strong waves or in streams with a moderate stream flow.
Currently found in the following counties:
Broadwater, Gallatin, Lake, Lincoln, Sanders
Download a distribution map from Montana Fish, Wildlife and Parks (2010)
Curley leaf pondweed can alter the nutrional dynamics of a fertile lake causing heavy summer algae blooms.
The life cycle of curlyleaf pondweed is very unique and makes it more competitive than other native plants. In the fall, the plant sprouts from dormant stem structures called turions which lie on the bottom of a body of water. Young plants can remain alive and active under ice during the winter and in the spring, their rapid growth creates dense mats which lie just below the water’s surface. These mats provide so much shade that it can suffocate other vegetation. In the late spring and early summer, the flower spikes arise above the water’s surface, and when plants mature, the fruit drops to the bottom of the body of water. Again, turions are produced when the parent plant dies and these drop to the bottom as well. They lie dormant until they are disturbed, then they break into fragments that are easily dispersed and root to produce new plants.
Commonly Confused Plants
- Claspingleaf Pondweed
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Photo Credits (top to bottom): Leslie J. Mehrhoff, University of Connecticut, Bugwood.org; © Paul Skawinski, Robert W. Freckmann Herbarium, University of Wisconsin - Stevens Point; Jane Mangold; © Paul Skawinski, Robert W. Freckmann Herbarium, University of Wisconsin - Stevens Point; Chris Evans, River to River CWMA, Bugwood.org