Weed Identification


Welcome to SePRO's Aquatic Weed Identification Guide. This guide will serve as your first step toward identifying and managing your aquatic weed problem. To get started, click on whichever group of aquatic weeds to which you feel your problem weed belongs and work through the examples until you find it.



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Wolffia spp.

Watermeal is recognized as the most difficult aquatic plant to control. It is the smallest of flowering plants; it can be dark to light green in color and resembles tiny grains of sand or cornmeal. It looks like very small dots covering the pond. Reproduction occurs by splitting, so complete coverage of a pond’s surface is rapid.

Also known as: meal weed; meal scum

White Water Lily

Nymphaea odorata

The white water lily is a perennial plant that often forms dense colonies. Water lily is one of the most recognizable floating aquatic plants. Sold as decorative plants for ponds and water gardens, this species can spread rapidly if left unmanaged. It is a rooted, emersed plant with large, notched, plate-like leaves with flowers that are white. The flowers may float or stick above the water and each opens in the morning and closes in the afternoon. The flowers are very fragrant.

Also known as: Fragrant water lily

Wild Rice

Zizania aquatica

Wild rice grows in shallow water, generally less than 3 feet. It looks like grass growing in the water. Late summer is when the seeds mature and look like oats or wheat. When the plants mature, they stand several feet above the surface of the water. During the growing season, wild rice is green, but when it is mature, the seeds are brown.

Also known as: - No listed alias -

Yellow Water Lily

Nymphaea mexicana

Yellow water lilies are perennial plants that arise on flexible stalks from rhizomes and large fleshy roots that can resemble bananas. Leaves are oval heart-shape, 3 to 6 inches in diameter, shiny dark green on top and reddish-purple underneath. Leaves float on the surface and are seldom emergent. Flowers are large (2 1/2 to 4 inches) bright yellow and usually stand above the water on separate stalks.

Also known as: Mexican Water Lily