Philodendron callosumPhilodendron callosum at a glance: Philodendron callosum is an adaptable species from Venezuela, Brazil, and the Guiana Shield that can grow on wood, on the ground, or even against rocky surfaces, which already sets it apart from fussier philodendrons. The foliage varies in size and texture depending on the conditions you give it, so it appeals to growers who enjoy a plant that responds visibly to how it is grown. Indoors it usually reaches around