I would start by reading Wilhelm Pelikens descriptions of the prep plants in 'Healing Plants'. Then have a read of what RS says about the function of the plants in the Agriculture Course, so you can get an image of what you are wanting. Then any other author I could find.
Then I would read up some herbal journals about the healing effects of your local plants, and try and match them up.
Part of RS approach is how plants effect the energetic activities, and this is what you need to match.