Place of origin
Originally from Eurasia and North Africa, Eurasian watermilfoil (Myriophyllum spicatum) was introduced to North America in 1961 in Lake Erie, Ontario. To our knowledge, Eurasian watermilfoil is currently not present in Alberta.
Habitat
Prefers shallow water but can root up to 10 m in depth.
Identification
Dense, floating mat formed by Eurasian watermilfoil that prevents light penetration into the water.
Eurasian watermilfoil stem with feather-like leaves around stem.
Stems and flower spikes of Eurasian watermilfoil.
Eurasian watermilfoil leaf with 12 or more closely spaced leaflet pairs.
- Perennial, submersed; flowers are very small, reddish and held above water on a flower spike.
- Usually 12 to 21 closely spaced leaflet pairs per leaf.
- Feather-like leaves collapse around stem when out of water.
Reproduction
- A single segment of stem and leaves can form a new colony.
- Plant does produce seeds but germination rates are usually poor.
- Stem fragmentation and underground runners allow this plant to reproduce rapidly.
Issues
- Forms large, floating mats that prevent light penetration into waterbodies, out-shading native plants and reducing oxygen levels when decomposing.
- Out-competes native milfoils.
Resources
Help stop the spread of invasive plants
Report aquatic invasive species:
- Phone: 1-855-336-2628 (BOAT)
- Online: EDDMapS
Learn more about identifying and preventing invasive aquatic plants:
- List of prohibited species
- Aquatic Invasive Species Pocket Guide
- ALMS Field Guide to Aquatic Plants
- Invasive Plants (Alberta Invasive Species Council)
Spread the word about the threats invasive plants pose:
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Invasive aquatic plants