Root foods and fish were the primary staples of the traditional Nez Perce diet. The "root foods" include all plants (usually hehen, "soft" herbaceous plants) with underground parts used for food: roots, bulbs, tubers, corms, and rhizomes. Nez Perce people enjoyed a great diversity of root food plants. Some neighboring groups had just a few kinds of root foods abundant in their home territories and relied on trade with the Nez Perce for roots that were unavailable.
The flowering of a root food plant (qe qi' t, Lomatium canbyi) marked the beginning of spring in traditional Nez Perce society. Root foods were dug with the efficiently designed digging stick, the tukus. The most important Nez Perce root foods were kouse (qaws, Lomatium spp., including the favored quqi t, L. canbyi), camas (qemes, Camassia quamash), and yampa (cawitx, Perideridia gairdneri and P. bolanderi). By far, more kouse and camas were stored for winter use than any other plant foods. Lomatiums were the earliest source of fresh spring greens, and other spring vegetables included shoots of balsamroot (pa'sx, Balsamorhiza spp.), yellowbells (stimex, Fritillaria pudica), onions (se'x, Allium spp.), and cow parsnip (Heracleum lanatum). Bitterroot (lita n, Lewisia redeviva) and wapato were also favored roots, although small quantities of these plants actually grow in Nez Perce territory. In the meadows of the foothills were wild onions, carrots, and other plants.