Large lake plants (called macrophytes) are an essential part of healthy lake and stream ecosystems. They are home to many aquatic animals and provide cover for young fish avoiding predators. Large lake plants also stabilize bottom sediments and reduce shoreline erosion.
Some rooted aquatic plants are weedy, especially exotic (non-native) invasive plants, such as Eurasian watermilfoil that first arrived in area lakes in the 1960s. Excessive growth of Eurasian watermilfoil makes it the most abundant rooted plant in the Dane County lakes.
This canopy-forming growth characteristic is what makes Eurasian watermilfoil such a nuisance to us. In particular, dense growth of the exotic plant interferes with boating and swimming, and the plants may produce an unpleasant odor when they die during summer. Eurasian water milfoil is usually the plant that lakeshore property owners, boaters and swimmers complain about, and with good reason. This weed (a "weed" is merely a plant out of place -- it is growing in the wrong spot) degrades the enjoyment and the ecology of the lakes.
As with many problem exotic species, we are unable to eliminate Eurasian watermilfoil from Dane County lakes. The plant continues to flourish in our lakes because the bottom sediments are a repository of excessive loads of nutrients from urban and rural runoff over more than 100 years. The goal for the most effective management is to mechanically harvest the plants where they are at nuisance levels and take the cuttings for composting in gardens.
Learn more about Aquatic Plant Management in Dane County.
Additional Aquatic Plant Resources
- Through the Looking Glass: A Field Guide to Aquatic plants (UW-Extension Lakes)
- Why Lakes Need Plants…and the ones they don’t need (Lake Access)
- Aquatic Plant Management and Protection Program (Wisconsin Department of Natural Resources)
- Aquatic Plant Guide (Minnesota Department of Natural Resources)