Bearded iris is a spectacular garden plant. Colors include pure white, brilliant yellow, soft apricot, deep violet, dark purple, and many subtle shades and combinations in between.
The outer three parts of the flower are called falls, which usually droop, and the upright petals are called standards. Inside, there are three more petal-like parts called style-branches. The bushy, beard-like hairs on the upper part of the falls give the plant its common name. Irises range from a few inches to almost 4 feet tall. The green, swordlike foliage is attractive all summer. The Schreiner's tall bearded iris ‘World Premier' (pictured here) received a John C. Wister medal, the highest award given to tall bearded iris.
Common name: Bearded iris
Botanical name: Iris germanica and hybrids
Plant type: Rhizome
Zones: 3 to 9
Height: 4 to 48 inches, depending on cultivar
- Sun: Full sun to part shade
- Soil: Well-drained neutral to slightly acidic soil is best. Add compost to sandy or clay soil.
- Moisture: Keep moist during the growing season.
- Mulch: Add 1 or 2 inches of organic mulch to keep weeds down, but keep it away from the leaves and rhizome to prevent rot. Protect with additional mulch during winter in colder climates.
- Pruning: Remove the flower stalk when it's finished blooming. After the first hard frost, cut iris plants to 6 inches tall.
- Fertilizer: Use a fertilizer with a 5-10-10 formula. Avoid fertilizer high in nitrogen (the first number).
- Sow seeds in the fall in a cold frame.
- Lift and divide clumps midsummer to early fall every two to five years
Pests and diseases:
- Iris borers attack both leaves and rhizomes. To control borers, dig and remove damaged rhizomes. A heavy infestation may require an application of a systemic insecticide to healthy plants. Also, consider choosing a new spot for irises.
- Slugs, snails, aphids, and nematodes may attack irises.
- Excessively wet planting spots damage rhizomes.
- Plant in midsummer to early autumn.
- Plant the rhizome so the tops are exposed and the roots spread out facing downward in the soil. (In very hot climates, you may cover with an inch of soil.) Space 6 to 8 inches apart.
- In dry weather, water deeply so plants have ample moisture.
- Irises make good cut flowers.
- ‘Devil's Lake' is medium blue and blooms mid- to late season. Grows to 39 inches tall.
- ‘Merlot' is a dark red to violet midseason bloomer that grows 37 inches tall.
- ‘Baby Blessed' is a dwarf bearded iris that's light yellow with a white spot and cream beard on each fall. It grows 10 inches tall.
All in the family
- There are about 300 species of iris, divided into two categories-Rhizomatous (bearded, beardless, and crested) and Bulbous. Several highly ornamental plants including Crocosmia, Crocus, Fressia, and Galadiolus are in the same family as the iris.
(Text by Mary Pestel, photo courtesy of Schreiner's Iris Garden)