Logwood is a bushy, thorny tree grown in Mexico, Central and South America and parts of Africa. The purple dye is concentrated in the heartwood of the tree. Dyeing: For a medium to dark colour use extract at only 0.5-1 % WOF on mordanted fibre. Dye at temperatures no higher than 180 F and for no longer then 60 min or the colour will lack clarity and luminosity.
See also Maiwa's Guide to Natural Dyes.