Weld gives yellows and olive greens with the use of iron, and gives the most brilliant emerald greens and teals when overdyed with indigo or Saxon blue.

Weld, reseda luteola, is a biennial plant native to Europe and Asia and has been used for millennia as an important natural dye.  Weld gives a very lightfast yellow and has often been over-dyed with indigo to make the most glorious emerald and teal greens that are very lightfast.  I have heard it mentioned to be the most lightfast yellow natural dye.

Weld is also known as Dyer’s Weld, Dyer’s Rocket, and Mignonette. Weld should be used with a mordant, alum for wool or protein fibers and aluminum acetate or aluminum lactate for cellulose fibers.

Dried weld gives a softer more buttery yellow than fresh weld which is best used before the flower/seed spikes mature.  All parts of the plant contain luteolin and are used for dyeing. When dyeing with the whole plant, you can use 30-50% plant matter to weight of fiber. 

Weld extract is very strong, and gives a strong yellow that can even have a hint of chartreuse to it. Use Weld extract at .25-.75% WOF (weight of fiber) for light colors.  1-2% for medium yellow.  3-5% for dark yellow.  Adding a pinch of soda ash or Calcium Carbonate (chalk) at 1% WOF brings out the brightest yellow of weld. 

25g of weld extract will dye approximately 800g (1.75 pounds) of fiber to a dark yellow shade. Adding a pinch of soda ash and calcium carbonate to weld while you are dissolving it deepens the shade and the color yield from the dyestuff. 

An online article by Catharine Ellis on The Effect of pH on Yellow Dyes from the Garden that can be found at her website https://blog.ellistextiles.com is interesting for further reading, in that she shows the difference chalking makes to the brilliance of weld. 

Weld is a biennial plant that grows a small leafy rosette and long taproot the first year and sends up a tall flowering stalk to produce seeds the 2nd year.  Bees really love the flowers stalks.  I have found weld to be somewhat challenging to grow in the ground, because it does like a bit of light to germinate and needs to stay moist when germinating and growing.  I can see why it has favored growing in English gardens, as their climate is said to be wetter. Because the plant has a single taproot, it doesn’t handle being transplanted as well, but once established, it is very hardy to cold. I did find that my plants did self-seed later in the year when there was a rainy spell, but before that, I can’t noticed any reseeding. So, now I start the seeds in potting soil and make sure to keep it moist while the seeds are germinating!

Weld should be used with a mordant, alum for wool or protein fibers and aluminum acetate or aluminum lactate for cellulose fibers.