A Witch Alone and Elements of Natural Witchcraft by Marion Green.
Mastering Herbalism by Paul Husson.
Green Witchcraft and others in this series by Ann Moura. (A tiny bit of Wicca mixed in, but clearly labelled when present).
Green Witch’s Formulary by Deborah Martin.
Traditional Witchcraft for Fields and Hedgerows by Melusine Draco and the other books in her series as well.
Witchcraft Medicine by Müller-Ebling, Rätsch, and Storl.
Sacred and Healing Herbal Beers by Stephen Buhner.
Hedge-Rider by Eric De-Vries, I offer this book with some reservations as the translation is so poor however the excellent books on this topic are either too expensive or written by jerks, so let me know if you know any better.