In Aristotle's classification of things, there are four tiers of life (paraphrasing): random stuff (rocks, plastic, etc.), plants, animals, and then humans are at the top. Thus, plants do contain what the authors refers to as "life force energy", but it's not unrealistic for the untrained mind to gaze upon a fruit tree and see it as the same thing as a rock or a piece of plastic.
If I were you, I would start with philosophers who have significant pop culture acceptance (Plato, Aristotle, etc.) to unlock your mind. You may think this guy who wrote the book I linked is crazy (completely understandable), but surely the most accepted philosophers of our time are not crazy, right? They write about many of the same concepts.
In particular, I would start with beginner explanations of the works of popular philosophers, because the original texts are translated directly from their native languages into English, and nearly impossible to understand no matter your level of English comprehension. The book I linked only makes sense to me because I discovered the concepts within Think and Grow Rich at a very young age and have been building from there.
EDIT: What the author refers to as "life force energy" is a synonym for "chi" in Asian cultures. The concept of "chi" is WIDELY accepted.
