Not in the way the term is usually used. Petroleum began as plants, but is generally considered a category separate from materials made from plants grown in our era. Plants that died 300 million years ago = fossil fuels and petrochemicals. Plants that were harvested by people living today = renewable resource. The distinction between "plant-based" and "petrochemical" may not be strictly valid, but it is useful to distinguish between renewable and non-renewable resources, since something that took 300 million years to make, and required conditions that may never exist again on the Earth, is in human terms a finite, limited, non-renewable resource; while something grown on farms today is a renewable resource.
if I'm not mistaken, petro was never plant matter. Oil is, I believe, the remains of marine organisms that's been heated. Coal, OTOH, is the result of compressed/heated plant material.
