Myriophyllum spicatum - Visit ITIS for full scientific classification.
- Submerged waterweeds form dense mats.
- Stems commonly reach 13 (and can be 23) feet long.
- Feathery leaves are 1" - 3" long and wide, usually in groups of 4 spaced along the stem.
- Part of plant emerges from water to produce 1" - 3" long flowering spikes with small, pinkish, male and female flowers.
- Usually found in still or slow-moving and sometimes in fast-moving, freshwater habitats.
Invasion Pathways and Distribution
- Possibly introduced as an ornamental aquarium plant.
- Found mostly in temperate zone of Northern Hemisphere, but also in subtropical and tropical areas.
- Occurs in central-western California, San Joaquin Valley, southern Sacramento Valley and Lake Tahoe.
- Spread by stem pieces carried by boating and fishing activities, on feet of water fowl and mechanical harvesting intended to control it, or discarded from aquariums and ponds.
- Produces seeds but seedlngs are rarely seen.
- Buds break off easily and sprout new plants.
- Dense mats interfere with water flow, boating and other recreational activities.
- They create mosquito habitat and crowd out native plants.
References and Useful Links
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