Madder

Rubia tinctorium

Originating in countries around the Mediterranian, Madder is historically one of the most important dyes. It yields the richest red shades obtainable from plant sources, both on animal and vegetable fibres. It is responsible for the warmth and richness of traditional Persian and Turkish carpets, where the ability of the dye to "fade gracefully" is an important selling point.

Madder is a perennial herb related to Goosegrass and with a similar scrambling habit. Its hooked stems and leaves cling on to any form of support, helping the plant to gain height - otherwise it just spraws on the ground. It can be grown from seed or offsets and it is the fleshy root of the plant that yields the valuable red dye.

Cultivation

Madder can be quite tricky to grow from seed as there are chemical inhibitors in the coat of the seed that prevent it from germinating. Germination rates of less than 20% are not uncommon, and can be much worse with seed that has been stored for a time. Soaking the seed before sowing can help, and although soaking in hot water (90 degrees centigrade for 10 minutes) is said to give good results, I have had little success with this method.

I have obtained the best germination by sowing the seeds in May at a temperature of about 24 degrees centigrade and keeping them well-watered.

Once you have a stock of plants, it is easy to propagate Madder vegetively, by severing "suckers" that the plant produces around the main crown.

Madder prefers deep, moist soil. Harvesting will be easier if the soil is relatively stone-free. It likes plenty of water and sunshine - the latter being essential for good dye production.

If you start from seed, grow the seedings on in small pots and plant them out in mid summer. Offsets can be planted directly in the final position. Allow 18 inches to 2 feet (45 to 60 cm) between plants. To keep the plants tidy, you can provide support in the form of twiggy branches or string for them to cling to.

Harvest and Preservation

Allow the plants to grow for two to three years before harvesting the roots. For maximum dye content, the end of August is supposed to be the optimum time, but you can dig them up any time from then to the following February. The roots can be used fresh, or they can be quite easily dried for storage. Wash the roots in cold water to remove soil. If you want to store them, spread the roots out in the sun or a warm, airy place. Be sure the roots are crisp, then crush or grind them before packing them in jars, pots or paper bags.

Dyeing

The roots of madder contain several dye chemicals, the most sought-after being alizarin, which produces the rich red shade with alum mordant. Obtaining a good red can be quite tricky, as the chemicals that give yellow and brown seem to be more easily extracted.

The usual method is to place the mordanted wool in the pot with the madder. For a good, strong red, use 100% madder (i.e. the same weight as the wool). You will probably want to place the madder roots in a fine-mesh bag to reduce the amount of root getting into the fibre. Hard water is best, and some people add chalk to the dyebath. If you are using dried roots, let them soak for 12 hours before dyeing. Raise the temperature to almost 40 degrees celcius, then add the wool, previously mordanted with alum. Keep the temperature between 50 and 70 degrees: at high temperatures, the pseudopurpurin is converted to purpurin, which will turn your dye more brown. Slowly and gently seems to give the best shade of red.

Besides alizarin, madder contains several chemicals that produce shades of brown and yellow. With an iron mordant, a plum or purple shade can be obtained, provided the temperature is kept low.