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  • Writer's pictureDon Yurewicz

Spiny Naiad (Najas minor), aka European Naiad - Invasive

Updated: Dec 9, 2022

Spiny Naiad is currently found in 7 locations within New Hampshire!


Spiny Naiad is a submersed rooted or floating plant.

  • Leave are paired, sometimes appearing whorled, and usually bunched at leaf axils.

  • The leaves are typically stiff, curled and pointed, and have spines along the margins that are visible to the naked eye, if not a hand lens. Leaves are about 1 mm wide and 0.5 to 3.5 cm long (Haynes 1979).

Look Alikes: This plant is distinguishable from native water naiad by its thicker and broader leaves with serrated edges.


Spiny naiad can spread by fragmentation during the growing season. Once introduced, it spreads rapidly and may completely cover the lake bottom, out-competing native plant species for space. It may grow along with other invasive plants, or form dense monotypic (single species) stands. If this plant becomes dominant, it may create conditions that are detrimental to native fish and waterfowl. Spiny naiad may also interfere with recreational activities such as boating, swimming and fishing

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