Eurasian Watermilfoil, scientifically named Myriophyllum spicatum, is distinguished by its soft, finely divided, feather-like leaves arranged in symmetrical whorls around flexible stems. This gives Myriophyllum spicatum a plume-like silhouette underwater. Native to Europe and Asia, it has colonized lakes and reservoirs around the world and is now one of the most widespread invasive aquatic plants.

It spreads aggressively through tiny stem fragments, allowing even a few nodes to start a new colony. Dense surface mats formed by Myriophyllum spicatum block sunlight, reduce oxygen, and hinder native plant growth. These mats can alter fish movement, change nutrient cycles, and interfere with recreation. Although feathery and delicate in appearance, the species is among the most competitive and disruptive freshwater plants globally.