Nuphar advena aka Spatter Dock

Nuphar advena is an aquatic perennial in the water-lily family. Common names include American spatterdock and yellow pond lily. Its native range runs from southeastern Canada to eastern Mexico. It also grows in Cuba. It lives in ponds, lakes, marshes, and slow streams. Other sites include canals, ditches, springs, and tidal waters. Its range spans temperate regions and reaches the tropics in Cuba.

The plant roots in mud beneath the water. A large, spongy rhizome creeps through this mud. Large, heart-shaped leaves float in a broad rosette. Leaves reach about 1.1–1.3 feet [0.35–0.40 metres] long. They measure about 0.7–0.8 feet [0.20–0.25 metres] across. The rosette can spread 8.2 feet [2.5 metres] or more. This broad form suits ponds with room for its spread. The species varies greatly where its range meets related species.

Plants For A Future gives July to August as flowering time. Each flower has both male and female organs. Flies and beetles pollinate the flowers. Gardeners can raise new plants from ripe seed. Sow the seed in pots beneath shallow water. Young seedlings need at least two years under greenhouse care. Plant them outside in late spring. Division in May offers another way to grow new plants. Each piece needs at least one growing bud.

Grow this plant in rich soil beneath still water. It also tolerates water with a slow current. A depth up to 2 feet [0.60 metres] suits it. Choose a sunny site, though light shade also works. It accepts sandy, loamy, and clay soils. It tolerates mildly acid, neutral, and mildly alkaline conditions. Plants For A Future lists USDA zones 3–7. Useful Tropical Plants reports dormant survival near −20°C. New growth can suffer severe harm at 0°C. Gardeners grow it as an ornamental pond plant.

People harvest the roots and seeds for food. Plants For A Future lists both as edible raw or cooked. Soaking the roots helps remove their bitter taste. Dried root flour can thicken soups or supplement baking flour. Roasted seeds can also serve as a thickener. The sources record traditional root treatments for bleeding and digestive complaints. They also describe root poultices for swollen or inflamed skin. These records describe past uses, not proof of safe treatment. Both plant-use sources report no known hazards.