Castor bean plants, which are not beans at all, are commonly grown in the garden for their striking foliage as well as shade cover. Castor bean plants are stunning with their mammoth star-shaped leaves that can reach 3' in length. Many varieties of ornamental castor beans are available and make a bold statement in any garden. Castor plants like full sun and humid conditions. Provide loamy, moist, but not soaking wet, soil for best results.