Native to: Europe, Asia, Africa and Australia
The first known collection of Curlyleaf pondweed in North America is from Philadelphia in 1841. It spread to the Great Lakes region in the early 1900s and is now found in all of the contiguous 48 states. It is thought to have been distributed primarily through boat and fish hatchery activity. While not currently problematic in Florida it is highly invasive and restricted in other parts of the United States and Canada.
Special thanks to Frank Koshere, Water Resource Biologist and Aquatic Plant Management Coordinator with the State of Wisconsin’s Department of Natural Resources for the use of his images. Please direct photographic inquiries to email@example.com.
Habit: Rooted, submersed aquatic plant.
Leaves and Stem: Wavy, lasagna-like leaves grow approximately a half-inch wide and two to three inches long with an obvious mid-vein, “toothed” or serrated edges and blunt tips. Arranged alternately, directly attached to the stem, and become denser toward the end of the stem. Main stem can be various colors including white, green, brown, and red, and tends to branch multiple times near the top of the plant.
Flowers: Flower stalk grows up above the water surface to about one inch tall and appears reddish-brown in the water but is actually green when examined closely.
Turions: Brown, typically a half-inch in size and look like sharp small pinecones.
Distribution in Florida: Vouchered from Jackson and Seminole counties.
Curlyleaf pondweed reproduces primarily by producing turions and rhizomes. It forms dense mats on the water’s surface inhibiting recreational activities. It can also obstruct water flow and exacerbate flooding. Dense surface mats of plant material limit light to low-growing submersed native species and can stagnate the water column inhibiting oxygen exchange from the surface to the water’s bottom. Decomposing plant material under the weedy canopy further reduces dissolved oxygen levels in the water column. These conditions can reduce or eliminate fish and aquatic invertebrates.
Clean all boating equipment and gear before leaving aquatic areas.
Small infestations can be hand pulled or raked.
Harvesting will not eliminate it but can mitigate the impacts to recreational activities and remove plant biomass.
Grass carp may feed on it.
Several aquatic herbicides – including diquat, endothall, flumioxazin, fluridone, penoxsulam, bispyribac and imazamox – can be used to effectively control Curlyleaf pondweed. Detailed information can be found here: Biology and Control of Aquatic Plants Chapter 2.4.
Consult your local UF IFAS Extension Office for management recommendations.