I finally hit upon the look I want for the comic.
And here is Vorpal. You know Vorpal, of course- born Keith O'Neil, became the Cheshire cat, does super-heroics, it's not exactly the most serious person on earth.

The poor guy who has to bear with him? That's GreenJack, Bradfield O'Loughain, the son of famous botanist Olivier O'Loughain and the Hamadryad Karya. GreenJack possesses an affinity with many natural beings, but his powers exert a direct control over the vegetable kingdom, capable as he is of mimicking properties such as developing actual barkskin for protection, or growing the explosive seed pods of the Hura crepitans tree (which explode sending their aforementioned seeds at 160mph) as defensive weapons, or producing both poison and healing solutions, and finally to grow, manipulate and control surrounding flora.

GreenJack is also capable of indirectly controlling mammals and insects in the various ways that several plants have developed through their particular evolutions. Being a hybrid of human and Hamadryad, Bradfield could be considered a 'tree' of sorts. And, of course, what kind of cat could resist climbing a tree?