How to Grow Dutch Iris
Iris x hollandica
Dutch irises grow from bulbs planted 10-15cm deep in autumn in full sun and well-drained soil. They flower in May-June with elegant bicolor blooms on tall slender stems, making them superb cut flowers. After flowering the foliage dies back and bulbs go dormant through summer. In heavy or wet soils, lift bulbs after the foliage yellows and store dry until autumn replanting. In well-drained soil they can be left in the ground year-round. Hardy to about -15C but benefit from a winter mulch in exposed sites.
Yearly Lifecycle
Care Requirements
Light
Full sun; at least 6 hours direct sunlight
Full sun is essential. Dutch irises need at least 6 hours of direct sunlight for strong stems and reliable flowering. They will not flower well in shade.
Watering
Minimal; avoid summer watering during dormancy
Water after planting in autumn to settle bulbs, then let rainfall do the work. Once established, they are drought-tolerant during dormancy. Avoid summer irrigation which causes bulb rot.
Fertilizing
Balanced bulb feed at emergence in spring
Apply a balanced bulb fertiliser when shoots emerge in spring. No feeding needed after flowering as bulbs enter dormancy.
Pruning
Remove spent stems; let foliage die back naturally
Remove spent flower stems after blooming. Allow foliage to die back naturally before removing. Do not cut green leaves as they feed the bulb.
Growing Tips
Plant in autumn for spring flowers
Plant bulbs in October-November, 10-15cm deep and 10cm apart in groups of 5-7 for the best display. Choose a spot with full sun and sharp drainage.
Excellent cut flowers
Cut stems when the first bud shows colour but before it fully opens. They will last 7-10 days in a vase. Cut in the morning for longest vase life.
Lift in wet climates
Dutch iris bulbs rot in wet summer soil. If your soil is heavy clay or stays damp, lift bulbs after the foliage dies back, dry them in the sun, and store in a cool dry place until autumn replanting.
Leave foliage to die back naturally
Do not cut back the foliage after flowering. The leaves feed the bulb for next year. Wait until foliage has yellowed completely before removing or lifting.
Spacing & Planting
| Plant spacing | 10 cm |
| Row spacing | 15 cm |
| Mature height | 55 cm |
| Mature spread | 10 cm |
Plant bulbs 10-15cm apart and 10-15cm deep in autumn. Can be planted in clusters of 5-7 for impact.
