I don’t “do” spell correspondence charts with herbs. If I’m really desperate for an herb for a particular spell I’ll go to one of Paul Beyerl’s excellent books. Number 1, because I’ve taken many classes from him and he’s a friend and I trust him and Number 2, he’s a gardener and a excellent researcher of herbal properties.
I think the best way to learn correspondences is to grow the herb. I never use an herb I haven’t grown at least once so it’s lucky I live in California where a good share of the herbs can be grown since a great many of the most common are Mediterrean in origin.
So how do I decide? By the properties of the herb itself. If it has thorns or a really strong odor it’s probably good for protection. If it smell sweet or attractive it’s probably good for love or friendship. If it doesn’t allow other plants to grow near it or smells vile, it may be good for banishment. Etc.
But I also know the constituents of a plant and how its chemistry affects things. If it is a healing plant externally it may not be good internally, a good example would be comfrey which can be very soothing in a salve but carcinogenic when taken internally. Mugwort is excellent for bug bites, nettle stings but if taken internally is a hallucinogenic and can enhance a tendency to mediumship which I found out to my detriment one Hallows when we drank it in a tea before going into a group trance.
When I trance it’s like leaving the porch light on and I attract things. Things can get frustrated if they have been trying to make contact and can’t find anyone to listen. This causes them to get really excited when someone finally can hear them. I’m still not sure if it was the being it said it was. All I know was that she was big, really big, bigger than my head could hold and I was not in the mood to give over any space there to someone I had not been formally introduced to and some one speaking such an archaic form of Scottish Gaelic as to be virtually un-understandable. That was one whopper of a headache and all because I opened the front door unwisely. And it took awhile to get the door shut again afterwards.
I do rely on tradition when the tradition is strongly in the culture. Things like oak being associated with strength knowledge and longevity are both actually true of the tree but strong in centuries of tradition in many people.
I used to have an incense and oil business so I learned a lot about what should and should not be combined and what can be burned safely and what should not be burned indoors. I also found out that for some people all incense smells like dope which was interesting to learn.
I also don’t use colour correspondence charts and sometimes my students would get really miffed at me when I wouldn’t but I think colour is incredibly personal. For one person yellow is a colour of joy and sunlight and for someone else it’s the colour of pee or cowardice. We all have our own internal dictionaries from our own experiences and just because someone says blue is for peacefulness and you hate blue means it probably won’t work for you. I hate pink therefore I would never use pink for affection as some of the charts say.
I’m a practical witch/druid/magic user. I do my own research. Over the last few years I have also learned not to use incestuous new age sources because they all seem to have plagiarized each other half the time. I’ve also had my butt kicked enough times by making mistakes to take a lot with a grain of salt and not go wide-eyed blindly believing anything anyone says. I fear the little boy from the Emperor’s New Clothes is strong in me. And quite frankly no one should blindly believe anything I say either without trying it for themselves. I’ve frustrated an awful lot of my students that way who wanted it given to them. Not going to happen.