Although quite hard to find in England (for cheap..), Saffron seems to be used quite often in dying and staining fabrics.

Saffron (when dried) 

Saffron was originally gown in Greece and Southwest Asia. When thought of, most people relate it to saffron rice, or other yellow foods, but saffron has been used as a dye for years. It is also the most costly spice in the world by weight!
 
The saffron flower 


When saffron is dried after harvest, the heat and the enzyme action release and give saffron its distinctive aroma.

A common substitute for saffron can be safflower, which is similar, but less expensive and a more orange colour - rather than red.. Below is a picture of the Safflower