Common Duckweed (Lemna minor) is one of the world's smallest flowering plants, forming delicate mats of foliage barely a quarter-inch tall across still water surfaces. Native to Missouri and found throughout the world, this deciduous aquatic perennial spreads with remarkable speed under the right conditions, making it both a fascinating addition to water gardens and a plant that demands respect for its vigor. Hardy from zones 4 to 10, it thrives in full sun to partial shade and adapts equally well to ponds, rain gardens, or naturalized water features. Despite its tiny stature and rarely-visible insignificant flowers, duckweed has supported ecosystems and attracted waterfowl for centuries.
Partial Sun
Moderate
4-10
3in H x 36in W
—
High
Hover over chart points for details
Lemna minor earns its common name honestly: waterfowl love it, and it spreads so aggressively in ideal conditions that gardeners must actively manage it to prevent it from taking over. The plant survives winters through a clever mechanism, developing buds called turions that sink to the pond bottom in autumn and rise again with spring warmth. Its fronds are so minute that a single plant is barely visible to the naked eye, yet colonies can blanket water surfaces within weeks. In cooler spring and autumn temperatures, it thrives most vigorously, then slows as summer heat builds.
Common Duckweed shines as a water plant for rain gardens and naturalized pond systems where it filters nutrients and provides food for waterfowl. Gardeners use it to establish biological balance in water features, allowing it to spread naturally across still water surfaces. In rain gardens especially, it helps manage stormwater while supporting bird populations. It's also grown deliberately in water gardens for its ecological benefits, though its aggressive growth habit means it works best in contained water features where its spread can be monitored and excess plants removed as needed.
No timeline data available yet for this variety.
Introduce duckweed to outdoor water features after your last frost date by scattering small bunches directly onto still water surfaces. Choose calm water with little current, as the plants need stable conditions to establish.
Place small bunches of duckweed plants directly on still water surfaces in your pond or rain garden after your last frost date. No soil preparation is needed; the plants float freely.
Remove excess duckweed regularly by netting out plants as the colony spreads across the water surface. In frost-free climates where invasiveness is a concern, be especially diligent about removal to prevent the plant from overwhelming your water feature. During autumn, allow some plants to remain so they can develop overwintering buds.
Enter your ZIP code to see a personalized growing calendar for this plant.
“Lemna minor's story is one of global ubiquity and quiet importance. Sometimes called lesser duckweed to distinguish it from its relatives, this species has naturalized across continents and appears in still waters wherever conditions allow. In Missouri, its native range, it has persisted in sloughs, ponds, and slow-moving streams throughout the state for millennia, serving as food for waterfowl and a natural filter in freshwater ecosystems. Its widespread distribution suggests it arrived in new regions through natural dispersal methods and human movement of water plants, becoming so common that it often goes unnoticed despite its ecological significance.”