Pediomelum esculentum aka Indian Turnip

Pediomelum esculentum is a perennial in the pea family, Fabaceae. Sources also list it as Psoralea esculenta. Its common names include prairie turnip, breadroot, and prairie potato. It comes from central and west-central North America. Records extend from southern Canada through the central United States. It grows in prairies and rocky woods, including sites with lime-rich soil. It is not native to Britain or Ireland.

This small plant reaches about 1 foot (0.3 metres) tall. Its edible root stores starch, protein, and sugars. Flowers appear from May to July. Each flower has both male and female organs. Insects carry pollen between the flowers. Root nodules house bacteria that fix nitrogen from the air. The plant uses some of this nitrogen for growth. Nearby plants may also gain from this process.

Grow prairie turnip in full sun with good drainage. It cannot grow in shade. It accepts sandy, loamy, and clay soils when drainage suits it. Soil may be mildly acid, neutral, or mildly alkaline. It grows in either dry or moist ground. The cited USDA hardiness range is zones 4–8. Root damage is a major concern when growing this plant. Set young plants in their final sites while still small. Moving older plants can damage their roots beyond recovery. Division is also difficult and rarely works.

The root has a long history as food among Indigenous North American peoples. People eat it raw or cooked, or dry it for storage. Dried roots can be ground and mixed with cereal flour. This flour mixture can go into cakes and porridge. Reports describe a sweet taste like that of turnip. Harvest takes place as the tops die back. The root contains about 70 percent starch and 9 percent protein. It also contains about 5 percent sugars. Trials as a European food crop began around 1800, with little success.

Prairie turnip can grow in cultivated beds and help hold soil in place. Its nitrogen-fixing roots add another use in planted ground. Traditional remedies used the roots for digestive, throat, and chest complaints. These reports describe past use, not proven medical benefits. The plant contains furanocoumarins, which can make some people sensitive to sunlight. Its value as food does not remove that risk.