In older ages, a mystic versed in herbalism used herbs in two different ways: for their biochemical effect and for their homeopathic, psychic effect.
The biochemical side of using herbs improved and went on to become modern medicine. Unfortunately, the psychic side of using herbs hasn't improved much - maybe even declined.
How does a psychic herbalist use herbs?
First, the vast knowledge of herbs forms a psychic system - not unlike astrology. Such knowledge provides a framework for understanding mental and psychic processes.
Secondly, herbs can be used in a similar way as crystals. A crystal is a visible, material essence of a type of psychic energy. A psychic can use plants and herbs as tuning forks for psychic energies on the biological level. Understanding this way of using herbs to influence the flow of psychic energies results in the homeopathic effect when used for healing.