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Water spinach, swamp morning-glory

(Ipomoea aquatica)

Photo of water spinach
Photo credit: Eric Guinther

This plant can form a large, dense, floating mat of intertwined stems that shade submerged aquatic and emergent vegetation. Small fragments of this plant can produce new plants with a fast growth rate of approximately 4 inches per day. This presents a threat to rivers, lakes and wetlands.

 Overview map of prohibited classification in WI
Prohibited (red) counties

Other names for this plant include:

  • Common names: Kangkong, river spinach, Chinese spinach, water convolvulus
  • Scientific names: Ipomoea reptans; Ipomoea subdentata; Convolvulus reptans

Classification in Wisconsin: Prohibited

Ecological Threat
  • Dense and tangled mats of fast-growing vegetation can obstruct water flow and access to open water.
  • Water spinach can grow in various habitats, such as lakes, ponds, wetlands and streams, shading out native plants important for fish and wildlife.
  • The floating vegetation mats formed by water spinach can create stagnant water below that is ideal habitat for breeding mosquitoes.
Identification

Leaves: Water spinach leaves are usually green and arrowhead or lanceolate in shape. The leaves grow alternately on the plant's stems, 2 to 6 inches long and up to 3 inches wide.

Flowers: Typically look like "morning glory" flowers. They are trumpet-shaped and showy, white to pale pink or lilac in color and grow singly or in small groups.

Fruits & seeds: Fruits are an oval or spherical capsule, woody at maturity, 0.5 inches wide; each capsule holds 1-4 grayish seeds. The pods and seeds can easily float and travel to spread new plants.

Roots: Roots are found at the nodes of the stems. Water spinach easily forms new plants when stem fragments break off and take root.

Stems: The stems are hollow and trailing, usually up to 3 meters (9 feet) but often much longer. The stems are herbaceous and have a milky sap. The limbs float in tangled mats where the plant grows on the water.

Similar species: Other species of Ipomoea or Convolvulus such as field bindweed, sweet potato or morning glory have identical flowers and leaves but lack hollow floating stems.

Distribution

Currently, there have been no reports of water spinach in Wisconsin. Have you seen it? Please send us a report.

Control

Mechanical: Not feasible to cut as the plant readily spreads from fragments. Hand-pulling is one option if all details are collected and destroyed.

Chemical: Aquatic-approved formulas of 2,4-D or glyphosate have had varying levels of success.

Resources
Sources for content: Links for more information: