Eleocharis dulcis
Common Name: Chinese water chestnut
Type: Rush or Sedge
Family: Cyperaceae
Native Range: Asia
Zone: 9 to 11
Height: 1.00 to 3.00 feet
Spread: 1.00 to 3.00 feet
Bloom Time: Rarely flowers
Bloom Description: Yellow-brown
Sun: Full sun to part shade
Water: Wet
Maintenance: Low
Suggested Use: Annual, Water Plant, Rain Garden
Flower: Insignificant

Culture

Winter hardy to USDA Zones 9-11. In warm areas where plants will survive winter outdoors, grow in mud/moist sandy loams or as marginals in water to 6” deep in full sun to part shade. Plants can be grown in ponds, bogs or other shallow water areas. Propagate by dividing the tubers. In St. Louis, plants will not survive winter outdoors, but (1) they may be overwintered indoors in containers in bright indoor light, or (2) the tubers can be harvested for storage in moist conditions until spring or (3) the tubers can simply be harvested for use as food. Plants can also be grown as annuals by repurchasing tubers each spring at an Asian grocery store. Plants generally need a frost-free growing season of about seven months in order to produce a good crop of tubers.

Noteworthy Characteristics

Eleocharis dulcis, commonly called Chinese water chestnut, is a tuberous, rush-like, marginal aquatic perennial that is probably grown more often for its edible, dark brown tubers (corms) than it is grown for ornamental purposes. Plants produce horizontal rhizomes that terminate in rounded tubers. The tubers are commonly used in Asian cooking. They may be eaten raw or cooked, and are noted for their sweetness and distinctive nut-like crunch. These plants are commercially cultivated in China and Japan for the tubers. Each tuber produces a dense clump of erect, branchless, green stems, many of which are topped by a cylindrical, straw-brown, flower spikelet (to 2” long). Flowering is uncommon for plants growing in the St. Louis area. Stem leaves are bladeless sheaths, with the stems actually providing the photosynthesis for the plant. Synonymous with Eleocharis tuberosa.

Specific epithet means sweet.

Problems

No serious insect or disease problems.

Garden Uses

Ornamental for water gardens or bog gardens or along streams. Harvest the tubers.