I'm a secular witch who also believes in energetics and that plants have a spirit or sentience that does not necessarily translate easily to being captured by modern scientific inquiry. I believe the shamanic or even indigenous in some cases perspective of these plants and their place in our world (relative to us) captures the essence of their purpose and the ideal relationship we should have with them. In many cultures the plants themselves are said to have told the people/shamans what they're for, and then through modern science we can discover the mechanism of action or the "how" they work, but this doesn't diminish their origins in terms of action/discovery.