Growing Bearded Irises These majestic flowers are surprisingly easy to grow, and actually require less attention than almost any other garden flowers. Your iris roots will arrive with the foliage "trimmed" from this spring's growth. You'll find the "root" is not really a bulb, but what is called a "rhizome"--an irregularly shaped bulbous root that grows at a right angle from the foliage. Leave the trimmed foliage as it is, and simply bury the rhizome with the top of it showing through the soil surface. Bearded irises grow best with the tops of their rhizomes exposed. Next spring, new foliage and the flower spikes will sprout strongly from the rhizome. What's more, next summer, you'll notice the rhizome multiplying for even more flowers as years go by.