[Wikipedia] Etymology, Uses: The common name 'ninebark' comes from the appearance of the flaky bark, seeming to have many layers.
Pacific ninebark was used as an emetic and a laxative by indigenous groups. The stems were used to make children's hunting bows and small items such as needles; straighter shoots were used to make arrows. The bark was mixed with cedar bark to make a dark brown dye. (link added by Mary Ann Machi)
Calflora:
Information on California plants for education, research and conservation,
with data contributed by
public and private institutions and individuals.
[web application]. 2025.The Calflora Database
[a non-profit organization].Available:
https://www.calflora.org/(Accessed: 03/29/2025).