Apios americana (Groundnut) - 2 gal

Groundnut, also called Wild Potato, is a native, compact, climbing vine in the pea family. It is a beloved Permaculture plant due to its value as a rare shade-tolerant Nitrogen-fixer. It has fragrant, maroon to lilac flowers June through September and its roots are long and cordlike with walnut-sized tubers attached. These tubers have a protein content triple the amount of potatoes and it is possible for each plant to produce five pounds of tubers. It was a significant food source for Native Americans, who taught the Pilgrims how to gather and cook them. The fruit and seeds are also edible.
Groundnut is a useful plant for wildlife as well. Deer will browse the foliage while the Silver-spotted Skipper and Southern Cloudywing use it as a larval host. Many bees are fond of this plant as a nectar source, including honeybees, bumblebees, leaf-cutting bees and Halictid bees.
This vine prefers to grow in average to high-quality environments with rich, moist to wet soils and partial to full shade conditions. It can grow rapidly, and may be aggressive and hard to control in its preferred setting. It is easier to manage if grown on a trellis with ample space. The tubers need at least one year from planting to mature into a sizable harvest.
Sources:
Eastern/Central Medicinal Plants and Herbs by Steven Foster and James A. Duke
Peterson Field Guide to Edible Wild Plants Eastern/Central North America by Lee Allen Peterson
Lady Bird Johnson Wildflower Center
Illinois Wildflowers
NC State Extension