u/No_Fail_845

I've done a bit of natural dying with foraging things (buddleia, walnuts, onion skins) using hot baths. I'm wanting to make a pair of stripy trousers using a wax resist but realise I'll need to use a cold dye to not melt the wax. Does anyone have any recommendations for something that can be foraged that dyes well on cotton in a cold bath?