Eurasian Water Milfoil

Report it

If you think you have found an aquatic invasive species:

1. do not return the species to the water
2. take photos
3. note:
   • the exact location (GPS coordinates)
   • the observation date
   • identifying features
4. contact us to report it

Identifying features

Eurasian Water Milfoil is a perennial that grows under the water surface. Its feather-like green leaves are arranged in whorls around the stem in groups of four or five. The leaves have 12 or more thread-like segments, and tiny pinkish flowers occur on reddish spikes that stand several inches above the water. The plant blooms in late July and early August.

Where it has been found

It was first observed in B.C. in 1970 in Okanagan Lake. The plant has spread since to Shuswap, Mara Christina and Champion lakes to all the main lakes in the Okanagan Valley, and to numerous water bodies in the Lower Mainland and Vancouver Island.

Habitat

This plant is found in wet areas at low to mid-elevation, where it grows in ditches, irrigation canals, marshes, streams and lake shorelines.

Ecological and economic impacts

Eurasian Water Milfoil grows and spreads rapidly while invading replacing native plants. It negatively impacts fish and wildlife populations as well as human activities such as swimming, boating, waterskiing, fishing and tourism in affected areas. This plant also has been known to impede flood control, water conservation and drainage and irrigation works. Milfoil populations can be very dense making it very costly to control.

Origins

Native to Eurasia and Africa.

Mode of dissemination

Fragments have the ability to disperse with water currents and regrow. Boats and boat trailers entangled with plants can transport Eurasion Water Milfoil to uninfested lakes.