Gladiolus is a classic perennial known for its tall flower spikes and large, colorful blooms. Great cutting flowers, gladioli look spectacular in summer bouquets. Here’s how to grow gladioli in your garden.Commonly called “glads,” these lovely flowering plants are available in a multitude of colors and typically reach between 2 and 5 feet in height. Their blooms also range in size—from “miniature” flowers less than 3 inches in diameter, to “giant” flowers greater than 5 inches across!