I think that a core principle of pemaculture is accepting the good in everything. I've rarely met a "weed" that didn't have a few redeeming qualities like breaking up disturbed soil, or some medicinal quality - well this thread is for music that encourages exactly that.
I haven't found the perfect song, but I will start us off with "Nothin' Grows in Shadows" - Permaculture would teach us otherwise, as mushrooms and hostas demonstrate, but I think the song's point fits.