Plant field guide
Iris (Siberian)
Elegant, long-lived perennial iris with fine grass-like foliage and delicate blooms in shades of violet-blue and white. More adaptable than bearded iris — tolerates moist soil and is deer resistant.
Growing requirements
- Scientific name
- Iris sibirica
- Sun
- full sun
- Water
- moderate
- Height
- 24 in (61 cm) – 36 in (91 cm)
- Spread
- 18 in (46 cm) – 24 in (61 cm)
- Spacing
- 18 in (46 cm)
- Hardiness zones & minimum temperature
- USDA 3–9; average annual extreme minimum from -40°F (-40.0°C). Hardiness does not predict local frost dates.
- Difficulty
- easy
Planting & seasonal timing
Northern Hemisphere planting months: not yet verified in our database.
Northern Hemisphere pruning months: October, November.
For the Southern Hemisphere, these seasonal windows shift approximately six months. Check your local frost forecast, soil temperature, and species requirements; calendar months are not a guarantee of planting safety.
Divide every 3–4 years when center of clump dies out. Does not need staking. Excellent around pond edges or in rain gardens. Foliage remains attractive through season.
Pruning
Cut foliage to 4–6 inches in late fall. Divide overcrowded clumps in early spring or fall.
Fertilizer
Balanced slow-release
Early spring
Mulch
2–3 inches organic mulch.