Weld has been used as early as the roman times for dyeing fabrics shades of yellow. When over-dyed with woad it produces Lincoln Green.
Harvest the leaves and flower stalks while the it is flowering but while the plant is still green. The leaves of nonflowering plants may also be used. Color is most concentrated in the leaves, flowers and seed pods. Old, dried up weld plants give a dull yellow.
Plant weld on 6” centers in full sun in average to poor soils. Height 2-4’ in flower. Leaves of 12 plants or tops of 6 flowering plants dyes 4oz of wool. Biennial.