it's been a while since I did any natural dying, but by usin different mordants you can achieve different colours form the same initial dye.
Onion skins work well, roots of various plants, eg. Alkanet.Acorns work well for grey or black but you need a little ferrous sulphate to help.
it's work playing, sadly not all the colours with be completely light fast, but it's fun to try.
the downside can be that the dyestuffs can help to shorten the life of the substrate.