Two type of marigolds pot marigold ( calendula officinalis) and the hybrid 'Art shades'
The pot marigolds have just started to flower, their bright orange/yellow has been used as colourant since the middle ages, it can also be used instead of saffron or sprinkled over salads. But as a natural dye for wool or silk, it will be mordanted with alum, equal weight of flower to silk. First the flower must be soaked in hot water overnight and then gently simmered to release the colour, this done in soft/rain water. The silk will be mordanted, then when the colour is extracted will be simmered in the dyebath, hopefully to produce yellow.
The other plant to be used is dried weld, similar quantities of the rather woody material to the silk. The plant material will be soaked for several days. Again a mordant will be used, but different colours can be expected with using iron or copper sulphate this will produce greens.
Pale green(better in real life) is weld/coppersulphate; yellow is weld/alum