Water Mimosa is a pantropical nitrogen-fixing legume that thrives in the unique niche between water and land, growing as a prostrate perennial in zones 9-12. This aquatic vegetable spreads across water surfaces and wet margins, reaching just 3-6 inches tall but capable of sending stems 3-5 feet across shallow water or pond edges. The plant produces showy flowers from June through September and can be grown in containers or floated directly on water, making it an unusual and functional addition to water gardens and rain gardens.
Partial Sun
Moderate
9-12
6in H x 60in W
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Moderate
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Water Mimosa develops white spongy air-conducting tissue (aerenchyma) when floating on water, giving stems natural buoyancy and allowing them to form dense foliage mats across pond surfaces. The plant fixes its own nitrogen, enriching water ecosystems without requiring supplemental fertilizers. Its low profile combined with sprawling stems and showy summer blooms creates a striking visual effect while producing edible foliage in a truly aquatic growing system.
Water Mimosa serves as both an ornamental and edible water plant. The foliage is edible and used in culinary applications in regions where the plant is grown, while its primary landscape value lies in water gardens, small ponds, and rain gardens where its floating mats of foliage and showy flowers create visual interest while helping filter and stabilize water systems.
No timeline data available yet for this variety.
Set out plants in spring after the last frost date when water temperatures have reached at least 70 degrees Fahrenheit. Position plant roots along water margins of ponds or water gardens with water covering the crowns, or float plants directly on still-water surfaces.
Harvest foliage as needed for culinary use. The edible portions can be gathered from the prostrate stems extending into the water. Timing and specific harvest cues are not documented in available sources.
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“Neptunia oleracea is a pantropical species naturally found growing prostrate in wet soils near water margins and floating freely in still-water areas across warm regions. Its distribution across tropical and subtropical zones speaks to its ancient adaptation to wetland environments, though detailed records of its introduction to cultivation or preservation by specific gardeners or seed savers are not documented in available sources.”