Sagittaria cuneata aka Arum Leaf Arrowhead

Sagittaria cuneata is a wetland perennial in the Alismataceae family. Its common names include wapato and arumleaf arrowhead. Its native range spans subarctic North America and much of Canada. It also grows across the northern, western, and central United States. Kew places it in temperate regions. It is not native to Britain or Ireland. The plant grows from underground tubers and reaches about 2.6 feet [0.8 metres].

Its form changes with the depth of the water. Plants in mud or shallow water have broad leaves. In deeper water, they may produce only long, narrow leafstalks. This range of forms can make plants look quite different. Flowers appear from July to August. Each flower is either male or female. Most plants bear both sexes, though some bear just one. Insects pollinate the flowers.

Wild plants grow along muddy shores and in shallow water. Their habitats include rivers, lakes, ponds, and ditches. They also occur in wet pastures and some tidal waters. Some grow in deeper water where the current moves slowly. In gardens, use a pond edge or bog garden. Give plants sun, since they do not grow in shade. Keep the soil wet, or grow them in shallow water. Still water and gentle flow both suit them.

Loam suits cultivation, but the plant also accepts sand and clay. It tolerates mildly acid, neutral, and alkaline soils, including very alkaline ground. PFAF lists it for USDA zones 5–9. Grow new plants from seed, tubers, or runners. Sow ripe seed in pots standing in shallow water. Increase the water depth as seedlings grow. Set young plants out in late spring or early summer. Divide the tubers in spring or autumn. Pot up runners during the growing season.

The roots and tubers are edible raw or cooked. Raw tubers can taste a little bitter; roasting makes them sweet. Tubers at the ends of the rootstock are preferred. Detached tubers float, which can help with gathering. PFAF notes potential use as a cultivated root crop. It also records traditional uses for headaches and indigestion. These records do not establish treatment benefits. PFAF lists no known hazards and does not flag weed potential.