Variable-leaf Watermilfoil
Photo by Meghan Johnstone, APIPP
Additional Images
Common Name: Variable-leaf watermilfoil
Scientific Name: Myriophyllum heterophyllum
Origin: Various regions of the United States
Description
Variable-leaf watermilfoil is a submerged perennial that looks like many native plants, including native watermilfoil species. It has 4-6 feathery leaves whorled around the stem, but some leaves can be alternate. Its leaves are divided into 7-14 pairs of leaflets, the dense leaf arrangement gives this plant a bottle brush appearance. Stems are thick and reddish-brown. In mid to late summer, blade-like, serrated leaves with small, reddish pink flowers form an erect spike that emerges from the water.
Habitat
This plant grows in a variety of depths, sediment types, and flowing conditions but typically is found in shallow bays and coves.
Threat
Plant fragments, which break off easily, can be transported from lake to lake on boat trailers or fishing gear. These fragments can start new populations, which form dense mats that degrade habitat and reduce recreational access.
Management
Once watermilfoil becomes well-established within a water-body, it is very difficult to remove. A variety of control methods to manage watermilfoil infestations include physical, mechanical, biological and chemical techniques.
Regional Distribution
Not Present
WNY PRISM Priority
Tier 1 – Raise Awareness
