Near each weaver's home, a large iron pot of water sits on a hearth of river rocks or metal and irons. Stoking the fire under the pot until the water simmers, she immerses roots, bark, hulls, berries, or leaves by the handful to make natural dyes that endure for decades or even centuries.
Vegetation for dyes include ripe berries of pokeweed (tsayatika) for pale red, oak galls (atagu) for rich red, anjelica leaves (wane-kita) for green,bark and roots of sumac (kwalaga) for brown, and yellow root (daloni-geunaste-tsi) for yellow. Through the long, complex development of Cherokee basketry, weavers have undoubtedly experimented with many indigenous and introduced plants for basketry materials. Any berry or nut or root that stained the fingers gathering them must have been potential dye.
From earliest memory, however, Cherokee weavers have chosen red, dark brown, and black hues for basketry. Black come from hulls, roots, or bark of butternut or white walnut (ko-hi), brown from hulls, roots, leaves or bark of black walnut (se-di), and red from roots of the bloodroot plant (gigageunaste-tsi). Material from black or white walnut trees can be gathered anytime of year, then dried and stored for use later. Though all parts of the tree can be used, the roots supply the most intense colors. Bloodroot is a nearly spring forb that thrives in the soil of deciduous forests. The fragile blossom that appears in early March is followed by deeply scalloped, blue-green leaves that grow through the summer. The orange-red dye comes from small rhizomes attached to multiple underground stems. The roots must be dug before the plant dies back in early autumn, for it leaves no sign of where it has grown. Weavers can dry and bury roots to store over fall and winter, but mold will cause rapid decay. In modern times, some weavers preserve bags of roots in their freezers.
Each color requires a separate pot of simmering water, which may account for the limited number of colors on baskets. To speed the dyeing and set the color, weavers might add a mordant. Before modern commercial mordants the mordant came from ashes, urine, or alum. Without mordants, splints take at least one full day to absorb brown or black walnut dyes. Red dye from bloodroot sets in a few hours. Weavers submerge the coils of splints into the simmering dye, weighing them down with rocks or heavy roots. Dyeing requires a watchful eye and plenty of time.
source: Weaving New Worlds by Sarah Hill