Water-Primrose reproduces rapidly, forming dense mats on the surface of the water. These mats can interfere with boat traffic and other recreational activities, as well as, reduce oxygen and light levels in the water column altering food and habitat for wildlife. They can also slow or completely halt water flow and cause sediment accumulations.

Water-Primrose is an aquatic invasive plant on the state of Michigan’s watch list. It is important to prevent, detect, and quickly control watch list species because if left unchecked they can spread rapidly with many negative impacts to the environment and economy.

Water Primrose was discovered in Macomb county in 2023. That same year the lake St. Clair CISMA surveyed 340 acres of Lake St. Clair Shoreline, aiding in early detection and rapid response efforts for this watch list species. Surveys for this invasive aquatic plant will continue during the summer of 2024.