Bearded irises prefer full sun, though in warmer regions they like some light shade. Grow these beauties in loose, fertile soil that has been amended with organic matter. Proper planting is very important. Plant iris rhizomes in well-drained soil in late summer. (1) Dig a hole large enough to accommodate all roots; form a ridge of soil in the bottom. (2) Spread roots out over the ridge. Add more soil as needed until rhizomes sit horizontal to the soil level. Cover with ½ inch of soil. (3) Divide the roots every 3 to 4 years to keep plants vigorous.
Iris borer is a major pest that tunnels into the thick rhizome. If you see spots like water streaks on leaves, feel the rhizome tops for soft spots; dig up any suspicious rhizomes to look for (and destroy) white borers inside. To reduce susceptibility, space plants 12 to 18 inches apart for best air circulation, and do not mulch.
Bearded irises provide flamboyance to any garden because they come in dwarf, intermediate, and tall sizes. The brilliant colors of the blossoms are often unique to the world of flowers and were created by complicated hybridization. Some people consider bearded irises untidy looking after the flowers fade, so they prefer to grow these delicious beauties in an area by themselves, or in a location where the swordlike leaves will be hidden by neighboring plants.
Bearded irises are available in tall (the most common), intermediate, and dwarf forms. Plant tall forms in the middle or back of perennial borders or in mass plantings. Intermediate types look charming toward the front of the border. Dwarf forms bloom slightly earlier than tall bearded varieties and make nice additions to rock and specialty gardens and near the front of the border.
ZONES: 3–10
BLOOM TIME: Early summer
LIGHT: Full sun
HEIGHT: 8–36 inches
INTEREST: Brilliant blooms; many sweetly fragrant