I've tried to give you surnames that are associated with nature and stone, as well as some color names as a nod to the first Pokémon region. Hope these help!
Ackerman (man of oak), Attwood (lives in the forest), Bentley (from the bent grass meadow), Bond (tied to the land), Caindale (from the clear river valley), Covyll (lives by the caves), Dagwood (from the bright one's forest), Ellwood (from the old forest), Graham (from the great meadow), Holcomb (from the deep valley), Huxley (inhospitable place), Lander (from the grassy plain), Maitland (from the meadow), Park (of the forest), Pitney (from the preserving land), Sherwood (from the bright forest), Stanwood (from the stony forest), Thornly (from the thorny meadow), Tilden (from the fertile valley), Worcester (from the alder forest), Aureolin (yellow), Cadmium, Chartreuse (green), Citron (bright green), Ebony (black), Viridian (green), Icterine (yellow), Keppel (green), Mahogany (brown, tree), Malachite (green mineral), Ochre (brownish color), Phlox (purple flower), Saffron (yellow), and Vermillion (red)