one of the most important colours for the house of bean is yellow, to match the van. therefore finding a good range of yellow natural dyes is very important.
below shows my first attempt at dyeing a t shirt using the bark from the alder birchwood tree. when dyeing the colour of the water is a very rich dark mustard colour (ideal) but after washing out this is the resultant colour - very pale but still a nice tone.
birchwood bark naturally contains tannin which is a mordant, so the addition of a chemical compound such as alum or iron will not have an impact on the colour
these trees are very common in the south west so is easy and free to obtain, my next experiment will be to use more of the dyestuff per weight and see if it strengthens the colour