Greater Duckweed is not a plant that draws crowds, but its role in the aquatic garden is disproportionate to its size. Each individual thallus — a flat oval barely a third of an inch across — combines the functions of leaf and stem into one compact structure, buoyant with tiny air pockets and anchored by a loose cluster of rootlets trailing beneath the surface. The upper side is medium green; the underside tends toward reddish-purple, giving a dense mat an unexpectedly rich palette when viewed from below. It thrives in still or slow-moving water from zones 5 to 11, forming the kind of living surface cover that shades out algae, moderates water temperature, and provides protein-rich forage for ducks, turtles, and the songbirds that visit pond edges.

For water garden use, Greater Duckweed performs best in a protected position away from wind and wave action — open water will disperse the colony and thin it out. Nutrient-rich water suits it well, making it a natural partner for ponds that receive runoff or house fish. In warm conditions it spreads rapidly, sometimes aggressively, and may need periodic thinning to keep it from monopolizing the surface. In cooler months it forms dense, starchy turions that sink to the pond floor and overwinter there, rising again in spring. Flowering is rare and functionally irrelevant — reproduction by budding is the plant's primary strategy, and it does that with quiet efficiency.