curlyleaf pondweed

Curlyleaf pondweed inhibits the growth of native species, interferes with recreational activities, and disrupts valuable services provided by native plants such as stabilizing sediment, improving water quality, and providing support for fish and other animals. MAISRC research includes analyzing data to determine factors that control curlyleaf distribution and abundance, establishing how many herbicide treatments are needed for control, and finding approaches to establish native plants after control. Click here to learn about curlyleaf pondweed research at MAISRC.

What it is

Curlyleaf pondweed is a non-native, invasive aquatic plant that can grow in very dense stands, displacing native species. One of its advantages is that it produces hardy turions – buds that can remain viable for long periods before sprouting to form new plants. Curlyleaf pondweed can grow in depths up to 15 feet.

Life cycle

Curlyleaf pondweed is generally the first pondweed to come up in spring, helping distinguish it from other native pondweeds. It dies in the mid-summer, and dead plants may accumulate on shorelines. Its primary means of reproduction is through the production of turions, hundreds of which can be produced by each plant. Turions remain dormant in the sediment through the summer and germinate in the fall. Germination rates can be as high as 80 percent, and turions can remain viable in the sediment for two or more years.  

What it affects

Curlyleaf pondweed displaces native plants, disrupting vegetation structure that provides forage and shelter for waterfowl, fish, invertebrates, and algae-consuming zooplankton. It also reduces recreational opportunities for swimmers and boaters by forming thick surface mats.

Where it’s found

Curlyleaf pondweed occurs in over 750 water bodies in Minnesota, spread throughout 70 out of the state’s 87 counties. It is native to Eurasia, Africa, and Australia, but is now found throughout much of the United States. 

How it spreads

Curlyleaf pondweed is spread by humans inadvertently transporting plants and/or fragments among waterbodies. Infestations often occur in high-use lakes.

What it looks like 

Curlyleaf pondweed produces a long stem (up to a meter) with small, submerged leaves that have distinct “teeth,” or wavy edges. In the spring, its turions look like small greenish-brown pinecones.