The Ficus family includes a large number of species including the rubber plant (Ficus elastica), weeping fig (Ficus benjamina) and fiddle-leaf fig (Ficus lyrata). Ficus grown as houseplants are much smaller than their outdoor counterparts, which grow in U.S. Department of Agriculture plant hardiness zones 10 through 12. Most ficus grown indoors are woody tree-like plants with single or multi-stemmed trunks. When caring for indoor ficus tree plants, the proper light, soil, pruning and fertilization are essential for a healthy plant.