Natural dyes from plants have been used for thousands of years. Madder (Rubia tinctorum), a bright red dye, was the red used for the famous British redcoats during the American Revolution. Indigo (Indigo tinctoris) produces a deep, rich blue. Indigo was used for the British naval uniform which is where the term "navy blue" originated.
One problem with natural dyes is that they would fade or wash out of the fabric unless you used a mordant. A mordant is a compound that will bond the dye color to the fabric. People used wood ashes, salt, rusty water, and vinegar as mordants. We now know that salts of metals such as tin, iron, copper, and aluminum are good mordants. Many plants can be used to create dyes of different colors:Plant SourceColorDandelionyellowBlueberriesblueBeetsredParsleygreenRed CabbagevioletWalnut Hullsbrown
Can you think of any plants that could be used to make a dye?
Black Walnut dye was used over white and gray wools to get this range of colors.
Plants such as marigolds, sage, Navajo tea, and onion skins were used to get a variety of colors.