Hydrilla
Hydrilla spreads rapidly and can completely clog waterways and restrict water flow, posing significant threats to aquatic ecosystems and recreational resources.
Common Name: Hydrilla
Scientific Name: Hydrilla verticillata
Native Range: Asia
Background
Hydrilla is a submerged perennial that looks similar to American waterweed (Elodea canadensis), a common native aquatic plant. Hydrilla has visibly toothed leaves that grow in whorls of 4-8. (Note: the leaves lower on the stem may be arranged as opposite or in whorls of 3.) Undersides may have one spine, or more, and the midrib of each leaf is often reddish. Hydrilla spreads by seeds, tubers, plant fragments, and turions (overwintering buds).
Habitat
This plant is tolerant of a wide range of environmental conditions and can be found in lakes, ponds, reservoirs, rivers, canals, and drainage ditches. It has low light requirements and thrives in both high and low-nutrient waters.
NYS Distribution Map
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Identification
Hydrilla leaves are typically in whorls of three or more, with five being most common. The outer edges of the pointed, bright green leaves have noticeably toothed edge. The plant produces a small, floating white flower that is attached to a thin stem. Hydrilla produces shite to yellowish tubers that can grow up to a foot long beneath the sediment.
Impact
Hydrilla spreads rapidly and can completely clog waterways and restrict water flow, posing significant threats to aquatic ecosystems and recreational resources.
Prevention and Control
A variety of techniques have been used in the U.S. to manage hydrilla including mechanical removal, physical habitat manipulation, herbicides, and biological agents. Prevention is the most effective control.
