Where does the connection between a particular spirit and a specific plant come from? I see/read a particular spirits plant all the time but where do these connections come from and where can I find out more. All of the above could be said for astrology, night/day, candle color etc.
Similar energies. In some cases the spirit may have established the plant species as a physical anchor similar to how some gods are associated to certain symbols, animals and plant.
Exactly. When you work with a Mars spirit, for example, anointing, burning and ingesting herbs with heavy Mars energy is going to help facilitate the flow. Pre-charging herbs in some cases can be awesome as well. This can also work with incense in general, food, etc…
Also growing the herbs yourself and working with them can be a initiation with the plant and its related energies all its own
But how do you know when there is so much conflicting info out there?
Begin with Meditating with or on the plant and as you do write down your impressions that come to mind. The resulting personal connection established through meditating can help you figure out which plants have synergy with which planets,spirits, elements ect.
Plant devas are the spirits attached to specific plants and herbs, you can actually work with these spirits to learn the esoteric properties of the plant in question and how to activate this and use them in your rites or potions.
There’s a whole magical lore about this and it’s fascinating to work through