Iris
Iris × robusta
- Native to:
- Canada, United States
Photo by and (c)2007 Derek Ramsey ( Ram-Man (en.wikipedia.org) )




Taxonomy
- Division:
- Magnoliophyta | - Flowering plants
- Family:
- Iridaceae
- Genus:
- Iris
- Species:
- Iris × robusta
- USDA Symbol:
- IRRO
Growth Characteristics
- Life Cycle:
- Perennial
- Growth Habit:
- Geophyte
- Height:
- 150 cm
- Light Requirements:
- Full Sun
- Drought Tolerance:
- Low
- Bloom Months:
- jun,jul
- Bloom Colors:
- violet, blue
Wildlife Benefits
- Butterflies & Moths:
- ★☆☆☆☆ Documented Lepidoptera association (GBIF)
Keystone Species Ranking
- Caterpillar Keystone:
- ★★☆☆☆ Butterfly & moth species supported by this genus (NWF)
Garden & Ecology Notes
- Wildlife Value:
- hummingbirds, butterflies
- Deer Resistant:
- Yes
Soil Requirements
- Soil Type:
- rich, moist, well-drained loamy soil
- pH:
- 5.5 - 7.0 (slightly acidic to neutral)
- Drainage:
- tolerates poor drainage
- Moisture:
- consistently moist
- Notes:
- Prefers wetlands or near water bodies
Propagation & Germination
- Stratification:
- Cold/moist stratification required — 60–90 days
- Germination Time:
- 30–180 days
- Notes:
- Germination can be erratic; best results from fresh seed sown in fall for natural cold stratification.
The above propagation data sourced from Claude AI
Pre-treatment: Cold-moist stratification for 30 days at 1–5°C (34–41°F).; then Cold-moist stratification for 60 days.
Notes: Seeds may require light for germination.
Source: Claude AI
ORGHPS Germination Guide: Expose to fluctuation outdoor winter temperatures including freezing for 3 months. Gradually increase light and temperature in the spring. * sow fresh or soak old seed; prechill 4 weeks or place outdoors over winter and bring indoors once germinated to avoid temperature shock; transplant at 4 leaves