Serratula tinctoria - A beautiful ancient dyer’s herb and medicinal plant. Dyer’s Saw-Wort is a source of a very durable yellow dye. It was well known in medieval times for the quality of the dye produced. Pretty purple thistle like flower heads, but are not spiny, held in clusters throughout summer. A long lived plant. Highly endangered in some of it natural habitats. Grows well in most well drained soils.