I do collect my own, when you buy them, you can never be sure what time of year they were collected, how old they are or how pure they are. I guess I'm kind of a control freak when it comes to that, also, you can't find gill in any herbal shop because the drying process destroys the medicinal properties, so it has to be used fresh.

Looking for recommendations for medicinal plants I should grow that are hardy in Zone 5 (New York) and how you use the plant. Hahom, Kauamarix

this isn't really something to "dabble" in. If you need someone to not only tell you what plants to plant, but also how to use them, what you should do is take a class It's too easy to hurt or even kill someone with this if you don't know what you are doing. There are thousands of medicinal plants that can grow in zone 5 (that's also my zone) but what specifically are you wanting to medicate? If you want a really useful book, get "the herbal PDR", it will at least give you how they interact with other herbs and medications.