How to Grow Iris (Pacific Coast)
Iris (Pacific Coast Hybrids)
Pacific Coast Hybrid irises are evergreen clump-forming perennials native to western North America. They prefer partial shade to full sun with acid to neutral, well-drained soil. Unlike bearded irises, they need cool, moist roots and dislike heavy clay. Plant in autumn or spring, water regularly until established, then they become drought-tolerant. Hardy to -15C. Divide only after flowering every 3-4 years if clumps become congested.
Yearly Lifecycle
Care Essentials
Light balanced feed in early spring as new growth emerges. Avoid lime-based fertilisers on acid-loving roots.
Watch For
- Iris borer (less common than in bearded iris)
- Crown rot in waterlogged soil
- Slugs on young foliage
Pet Safety
Care Requirements
Light
Partial shade to full sun
Prefers dappled shade or morning sun with afternoon shade. Tolerates full sun in cooler climates if roots are kept cool with mulch.
Watering
Regular until established, then drought-tolerant
Water regularly until well established. Once settled, surprisingly drought-tolerant in summer. Avoid waterlogging at all times as this causes crown rot.
Fertilizing
Light ericaceous feed in spring
Apply a light balanced or ericaceous feed in early spring. Avoid lime-based fertilisers which raise soil pH. A top-dressing of leaf mould is ideal.
Pruning
Remove spent flower stems only
Cut spent flower stems after blooming. Leave the evergreen foliage intact year-round. Divide congested clumps every 3-4 years immediately after flowering.
Growing Tips
Ensure acid to neutral soil
Pacific Coast irises are calcifuge and resent lime. If your soil is alkaline, grow in raised beds with ericaceous compost. A pH of 5.5-6.5 is ideal.
Never let roots dry out when transplanting
Unlike bearded iris, Pacific Coast hybrids have fine fibrous roots that desiccate quickly. Move divisions promptly into moist soil and water in well. Bare-root plants often fail; potted divisions establish best.
Provide cool root conditions
Mulch lightly with leaf mould or bark to keep roots cool in summer. These irises evolved under coastal oaks and conifers with dappled shade and cool soil.
Spacing & Planting
| Plant spacing | 30 cm |
| Row spacing | 40 cm |
| Mature height | 40 cm |
| Mature spread | 35 cm |
