Spiny Naiad Najas marina

Annual, Seasonal

  • English Name: Spiny Naiad
  • Latin Name: Najas marina
spiny weed

Lake weeds with teeth like spines

The popularity of the weed comes from the fact that it is usefully easier to tell apart from the other Naiad weeds. All Naiads - there are about 40 kinds across the world - are weeds with narrow leaves with edges that have tiny teeth-like spines. In some varieties, such as the Slender Naiad, the teeth are so tiny you can't see them with naked eyes while in others, such as the Southern Naiad, the leaves have blunt edges like a strap. All of them are also sometimes called nymph weeds, because the word Naiad is derived from the Greek equivalent for Goddess Nymph, a beautiful goddess that supposedly lived in mountains, rivers and lakes.

The Ways of the Spiny Naiads Invasive Lake Weeds

Beyond the saw-like leaves and the tolerance for alkaline water and poor sunlight, the Spiny Naiad shares the physical attributes, habits and lifestyle of the other Naiads. It is a rooted plant that is heavily branched and grows entirely under water. It is greenish with a tint of purple or brown in colder seasons. Its flowers and seeds are extra-tiny and hard to spot because they grow close to the leaves.

How to Eradicate the Spiny Naiad

he normal approach is to cut and rake the Spiny Naiad out of the water. The technique is fairly successful if done before the seeds mature and the twigs detach from the plant on their dispersal missions. One of our weed control products, the Deskuzzer, is particularly suited for the task because it has a long reach. It is a 5 foot wide floating seine with sturdy abrasion, ultra tough screen, and a 24 foot pull line that makes it easy to gather the weed.

A more thorough technique is to use another of our weed control tools, the Lake Bottom Blanket. This is a 10 feet wide sheet of specially treated polythene that is anchored in the water by weights so as to block out sunlight. It is made of lighter-than-water material, enabling it to remain suspended in the water without touching the water bed. That leaves plenty of space for fish and other aquatic animals to go about their business as usual.

The Blanket has already been proved effective in over 400 lakes in 29 states, with a 100% kill rate of weeds in less than four weeks. The Blanket is dark on one side and white on the other, a combination that totally blocks sunlight. Even the Spiny Naiad which can survive in limited sunlight cannot handle the sunless environment.

The Lake Bottom Blanket is approved for use by the DNRs and DEPs of California, Nevada, New York, Connecticut, Massachusetts, Washington.

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Quick Facts abobut Spiny Naiad




Mass of weed with slender, branching stems and tiny leaves edged in sawlike teeth


Chokes out other aquatic plant species

States effected

Common in southern and central US

Controlling methods

Raking, cutting, herbicide, benthic barriers

Controlling methods

Raking, cutting, herbicide, benthic barriers