If there's one resource i would recommend to just about anyone, its
"The Wild Wisdom of Weeds, 13 Essential Plants for Human Survival by Katrina Blair"
It has
medicinal uses (and edible uses) for weeds found worldwide. It is simple, clearly written and the author embraces
permaculture. I used to live in the UK, all these plants are widespread there (and for the uk specifically, I would suggest reading up on medicinal uses for
Nettles, those things are everywhere).
I cannot recommend this book
enough, it really helped me get my mindset away from exotic, expensive herbs imported from accross the world and instead looking right in my own neighbourhood and garden for healing herbs.