Witchipedia

Each Witch performs her magick in her own way so it can be hard to say what the intention of such a spell might be. If I were using that combination, it would be a spell to encourage someone to never forget the great sex we had. Seriously. Of course, I don't know what the tree bark is, that could switch things up altogether, and not everyone thinks of garlic as a sexy herb, and not everyone goes straight to memory when they see rosemary. If I were going to do this spell though, there would be a little poppet in there and I wouldn't use plastic (a glass jar or a cloth bag would be my preference) and I certainly wouldn't put it in your mailbox.

On the other hand, if I were making a healing soup, garlic, rosemary, ginger and astragalus bark are potent immunity enhancers and taste good in bone broth. Willow bark is good for pain and fever, though it's bitter (again, no idea what kind of bark we have here) and I might keep something I was going to use in a soup in a sandwich bag. I'd cook that up with some chicken bones and giblets till I got a nice dark, rich broth and keep it on hand for cold season.

But see, that's me. Each witch, or sometimes each coven, has their own way of doing things.