A Rex Begonia plant is grown for its large colorful leaves rather than its small pink flowers. Their leaves come in a variety of shapes, sizes, color combinations and patterns. These fancy-leafed begonias produce large leaves that are 6” long and 4-5” in width. Depending on the cultivar Rex Begonias average anywhere from 12” to almost 24” tall, with a similar width, when fully grown. They have a clumping and rounded growth habit and their foliage grows tightly packed together giving the plant density.