Purple Wen-dock Brasenia schreberi

Water Shield is an herbaceous perennial, aquatic, native plant with long, slender, branching stems. It resembles water lilies (Nymphaeaceae) because both are found submerged or floating on the water's surface. Water Shield, in particular, is found in nature on ponds, lakes, and sluggish streams throughout the world. It has creeping, thin rhizomes rooted in the mud at the bottom of ponds, floating leaves, and grows in a wide range of water depths (1 inch to 6 feet). It does best on the water edge in 8 to 10 inches of water, but with the roots planted in the mud of more shallow waters. The young leaf tips, which are coated with a thick transparent mucilage, are eaten in salad with vinegar, sake and soy sauce, or added to soups as a thickener. The plant is considered a delicacy in Japan where it is often bottled and sold in local markets.

The species name, schreberi, is for Johann Christian Daniel von Schreber, a German botanist and student of Linnaeus in the 18th century.

Water Shield has properties that inhibit the growth of other plants nearby. Thus, the plant can become dominant and provide a natural control of invasive water weeds. Water Shield is pollinated by the wind in a very unusual process. Individual flowers are open for a two-day period. On the first day the flower is open it is functionally female, with the stigmas receptive to pollen. At the end of the first day the flower is drawn below the water’s surface. On the second day the flower again extends above the water’s surface and the anthers release their pollen. The flower is then pulled below the water’s surface again and the fruit develop.

Diseases, Insect Pests. and Other Plant Problems:

No known diseases or insect pests. Water Shield is often considered a pest as its dense growth interferes with fishing, swimming, and boating.