If you are seeking to keep the growth of herbs at maximum, perhaps you should consider the animists guild. Not only are they focused on preserving the state of plant growth, they have skills available that maximize them. As a pacifist ranger, you lose many skills available to you - and even risk hurting the land by replanting without the full range of herb/poison enhancement options available to you.
I'm certain one so attuned to the needs of the land's plant life would be willing to make this sacrifice to ensure that the continent realizes its maximum herb/poison potential.
Written by my hand on the 19th of Springflower, in the year 1152.