Diliff / CC BY-SA 3.0
garden
Iris
Iris bismarckiana
Overview
Named for the Greek goddess of the rainbow, irises come in an astonishing palette of colors and are among the most iconic garden flowers worldwide. From the stately bearded irises to the moisture-loving Japanese and Louisiana irises, there is a type for virtually every garden condition. Orris root, derived from iris rhizomes, has been used in perfumery and gin production for centuries.
Growing Conditions
Hardiness Zones6 — 9
Height150.08m
Spread1m
Growth HabitForb/herb
Pollinator Valuemoderate
Companion Planting & Soil
Good Companions
Soil pH6 — 7.5
Soil TypeWell-drained soil with rhizomes at or near the surface; varies by type
Planting Calendar
When to sow, transplant, and harvest by growing zone.
| Zone | Action | Months | Notes |
|---|---|---|---|
| Cold (1-2) | Transplant | Jul — Aug | Plant rhizomes in midsummer; top of rhizome must be at soil surface — do not bury |
| Cold (1-2) | Bloom | May — Jun | Late spring bloom; remove spent stems but leave fan of leaves |
| Cool (3-4) | Transplant | Jul — Aug | Plant in summer; rhizome should bake in sun; excellent drainage |
| Cool (3-4) | Bloom | May — Jun | Spring bloom; reblooming varieties may flower again in fall |
| Moderate (5-7) | Transplant | Jul — Sep | Plant in late summer/early fall; do not mulch over rhizome — needs sun exposure |
| Moderate (5-7) | Bloom | Apr — Jun | Spring bloom; hundreds of color combinations available |
| Moderate (5-7) | Divide | Jul — Aug | Divide every 3-4 years after bloom; discard old center section; trim leaves to 6" fan |
| Warm (8-9) | Transplant | Sep — Oct | Plant in fall; bearded iris needs some winter chill; Louisiana iris thrives in warm zones |
| Warm (8-9) | Bloom | Mar — May | Early spring bloom; Louisiana iris blooms in wet soil |
| Hot (10+) | Transplant | Oct — Nov | Plant in fall; choose Louisiana or Japanese iris for hot humid areas |
| Hot (10+) | Bloom | Feb — Apr | Late winter/spring bloom |
Uses
Other Uses
- Iconic ornamental perennial in nearly every color
- Orris root used in high perfumery and potpourri
- Rain garden and water feature plantings (Japanese and Louisiana types)
