Common names: spike watermilfoil, Eurasian watermilfoil
Myriophyllum spicatum (spike watermilfoil) is a common submersed aquatic perennial (family Haloragaceae). Spike watermilfoil can be found in freshwater lakes, ponds, and canals with slow-moving waters in northern and central California, particularly in the San Francisco Bay and San Joaquin Valley regions and Lake Tahoe. This plant grows and spreads rapidly, creating dense mats on the water surface. These monotypic mats out-compete native aquatic plants, reducing species diversity.Cal-IPC Rating: High?
CDFA Rating: C?
Plant Assessment Form - Information gathered by Cal-IPC on the impacts, rate of spread, and distribution of invasive plants in California. Does not include management information.
Weed Management Notes
- Management Notes - Information on management techniques and effectiveness from the University of California Cooperative Extension’s Weed Research & Information Center.
Cal-IPC Newsletter Articles
- 2020 Symposium talks sampler. Cal-IPC. Vol 28, Issue 3
- Invasive species management in Lake Tahoe. Cartwright, Nicole; Johnson, Doug. Vol 26, Issue 3
- Chasing weeds from Maine to California. Stack, Lois Berg. Vol 16, Issue 4
- Fighting weeds in the Tahoe basin. Donaldson, Sue. Vol 11, Issue 2
- CalEPPC Symposium ’97. Warner, Peter. Vol 06, Issue 1
Cal-IPC Symposium Presentations
Presentations are linked where available. Where a presentation is not available, find more information by reading the abstract in the Cal-IPC Symposia Archive.
- Early detection and rapid response: effective weed control at the landscape level. Farrell, Sharon; Patterson, Jesse; Kesel, Rachel; Brigham, Christy; Gregory, Nathan; Gardner, Leah (2020)
- The role of public gardens as sentinels of plant invasion. Culley, Theresa; Dreisilker, Kurt; Ryan, Clair; Landel, Hans; Cavallin, Nadia; Arcate Schuler, Jessica; Shultz, Brittany; Gettig, Roger; Havens, Kayri (2020)
- Effectiveness of aquatic invasive plant control in Emerald Bay, Lake Tahoe. Shaw, Dan; Hymanson, Zach; Boyd, Kim; Sasaki, Tamara (2011)
- Applied ecology of Eurasian watermilfoil (Myriophyllum spicatum L.) in Fall River. Hunt, Thaddeus; DiTomaso, Joseph M.; Spencer, David F. (2007)
- Aquatic working group. Anderson, Lars; Zaremba, Katy; Owen, Julie; Crosson, Holly (2004)
- Aquatic weeds: Policy, prevention, and control. Anderson, Lars (2003)
- Getting the job done: Working within the regulatory environment at Lake Tahoe to manage weeds. Donaldson, Susan; West, Wendy; Taylor, Kirk (2003)
- Flood-borne noxious weeds: Impacts on riparian areas and wetlands. Donaldson, Susan G. (1997)
Other Myriophyllum spicatum Information
- CalPhotos - Images of plants taken mostly in California.
- Calflora - Distribution map and records of this species in California.
- CalWeedMapper - Distribution map of this species in California with ability to determine regional priorities.
- EDDMapS - Distribution of this species in North America.
- Jepson Interchange - Information on this plant's taxonomy, biology, and distribution from UC Berkeley's Jepson Herbarium.
- USDA PLANTS Database - Information on identification and distribution, with links to websites in individual states.