Bearded Irises
Bearded Irises need at least a half day of sun and not be shaded by other plants to bloom well. They prefer a well-drained, fertile, neutral to slightly acidic soil. They can be planted any time the soil is not frozen but a month after bloom is optimum and gives the best chance for bloom the following year. Plant so the top of the rhizome is at the soil surface. Plant Tall Bearded iris in groups of 3 or 5, 30 to 60 cm apart (1 to 2 feet) to give quick results. Dig a shallow hole up to 25 cm wide (10 inches) for Tall Bearded irises and 10 cm deep (4 inches). Make a ridge of soil down the middle and spread the roots on both sides. Fill the hole with soil and firm gently. Water thoroughly. Top dress with
Beardless Irises
Beardless Irises (Siberians, Spurias, Japanese etc.) also need at least half a day of sun to bloom well. They like a humus rich, well drained, moist, acidic soil. They are best transplanted in early spring, right after bloom, or in the early fall. Top dress with a balanced fertilizer in the early spring and after bloom. Japanese irises respond very well to
Further info on growing Irises is available at the American Iris Society: Cultural Information – planting and growing irises.