Carolyn Dodson and William W. Dunmire write about blue flax being native to America and used in weaving.
Carolyn Dodson and William W. Dunmire, Mountain Wildflowers of the Southern Rockies: Revealing Their Natural History (Albuquerque, NM: University of New Mexico Press, 2007), 70
DISCOVERY OF BLUE FLAX
When Meriweather Lewis, leader of the Lewis and Clark Expedition, first encountered blue flax he recognized that "the bark of the stem is thick and strong and appears as if it would make excellent flax." Indeed, pre-Columbian Native Americans used blue flax fiber for weaving and making fishing line. Frederick Pursh, who gave the botanical name to the plant, noted, "Flowers large, blue, a very good perennial, and it might probably become a useful plant if cultivated." Today blue flax is available in nurseries throughout the West.