Comfrey Books
https://nantahala-farm.com/ComfreyBooks-s.shtml
Volume 1
"Botany and History of Comfrey; Garden Uses of Comfrey"
A book with in-depth information about the Symphytum genus, its botanical classification,
characteristics of different species like Symphytum officinale (Common Comfrey), Symphytum x uplandicum (Russian Bocking), Symphytum asperum (Prickly Comfrey) and 46 other species. Garden uses include compost activator, fertilizer, and potting mix. How to grow fruits and
vegetables with comfrey fertilizer. Scientific analysis of the nutritional value of comfrey.
https://nantahala-farm.com/ComfreyBookVolume1--Symphytum-Botany-History-Garden-s.shtml
Volume 2
"Cultivation of Comfrey; Medicinal and Food Uses for People and Livestock"
A book about how to grow comfrey from seeds or cuttings, when/how to plant, soil/water needs, fertilization, and diseases/pests. How to harvest leaves and roots. How to make comfrey hay and silage. Symphytum as food and medicine for livestock, pets and humans. Its historical and modern medicinal applications. How to make and use comfrey medicine. Government regulations on comfrey and health risks. It provides extensive historical documents and modern research.
https://nantahala-farm.com/ComfreyBookVolume2--CultivationSymphytum-s.shtml