Long lived herbaceous perennial dye plant. Slightly scrappy to look at, the weak stems often lie along the ground, but can climb up to 1.5m high by means of tiny hooks. Leaves are formed in whorls starlike around the central stem. Flowers in mid-late summer are inconspicuous, with five pale yellow petals, followed by small (4–6 mm diameter) red to black berries in autumn, then the whole plant dies down in winter. The roots can be over a metre long, with side roots which run under the surface of the ground for some distance, sending up new shoots. Madder prefers loamy soils with a constant level of moisture.
Madder roots have been used as a dye for materials such as for leather, wool, cotton and silk for over 5,000 years. Archaeologists have found traces of madder in linen in Tutankhamen’s tomb (1350 BC), and in wool discovered in Norse burial grounds. The minimum age for harvesting is three years, but the best age is five years, when the roots are pencil thick. Fifteen-year old plants produce roots that are 2.5 cm in diameter. If you wish to harvest madder regularly it is best to have three or more beds, and dig them in rotation.
The outer red layer of the root gives the common variety of the dye, the inner yellow layer the refined variety. The dye is fixed to the cloth with help of a mordant, most commonly alum. The roots contain the acid ruberthyrin. By drying, fermenting, or a treatment with acids, this is changed to sugar, alizarin and purpurin. Purpurin is not coloured, but is red when dissolved in alkaline solutions; mixed with clay and treated with alum and ammonia, it gives a brilliant red colourant (madder lake).
9cm pot Certified Organic plant.
Plant photo: www.flickr.com/photos/melanieshawmedicalherbalist/7991378505
Dye photos reproduced with permission from Michelle Parrish www.localcolordyes.com