Iris missouriensis (Rocky Mountain Iris)
Rocky Mountain Iris, Western Blue Flag, Iris longipetala, Iris missouriensis var. arizonica, Iris missouriensis var. pelogonus, Iris pariensis, Iris tolmieana
Quite hardy, Iris missouriensis (Rocky Mountain Iris) is a spreading rhizomatous perennial boasting large, delicate, pale blue or blue-violet flowers, 2-3 in. long (5-7 cm), with deeply veined dark purple sepals adorned with a yellow-white signal. Blooming in late spring to early summer, 1-4 blossoms per stem, they are borne atop stout stalks that arise from dense clumps of long, narrow, arching blue-green leaves. The tough leaves are avoided by cattle and deer. Commonly found growing in wet meadows, dry steppes, and open woodland in western North America, this small rhizomatous perennial tolerates some dry soils once established but only after flowering. Rocky Mountain Iris is an excellent plant for sunny perennial borders or foundations.
- Grows up to 12-24 in. tall (30-60 cm) and 10-12 in. wide (25-30 cm). This plant will spread by rhizomes to form colonies.
- Performs best in full sun in medium to wet, fertile, slightly acidic, well-drained soils. Some afternoon shade is welcomed in hot summer areas.
- A welcomed addition to beds and borders, wall-side borders, city gardens, cottage gardens, and coastal gardens.
- Remove any dying foliage in fall, old flower stems can be cut down after flowering.
- Keep an eye out for slugs, snails, whiteflies, thrips, and gray mold. Deer resistant.
- All parts may cause discomfort if ingested. Wear gloves and other protective equipment when handling.
- Toxic to dogs, toxic to cats, toxic to horses.
- Propagate by division of rhizomes from midsummer to early fall.
- Native to North America, Mexico.
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Requirements
Hardiness | 3
– 9 |
---|---|
Heat Zones | 1
– 9 |
Climate Zones | 1, 1A, 1B, 2, 2A, 2B, 3, 3A, 3B, 4, 5, 6, 7, 8, 9, 10, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 |
Plant Type | Perennials |
Plant Family | Iris - Other |
Exposure | Full Sun, Partial Sun |
Season of Interest |
Spring (Late) Summer (Early) |
Height | 1' – 2' (30cm – 60cm) |
Spread | 10" – 1' (25cm – 30cm) |
Spacing | 12" – 20" (30cm – 50cm) |
Water Needs | Average, High |
Maintenance | Low |
Soil Type | Loam |
Soil pH | Acid, Neutral |
Soil Drainage | Moist but Well-Drained, Moisture Retentive |
Characteristics | Showy |
Native Plants | United States, California, Midwest, Minnesota, Nebraska, North Dakota, South Dakota, Pacific Northwest, Idaho, Oregon, Washington, Rocky Mountains, Colorado, Montana, Utah, Wyoming, Southwest, Nevada, Arizona, New Mexico |
Tolerance | Deer, Wet Soil |
Attracts | Hummingbirds |
Garden Uses | Beds and Borders, Wall-Side Borders |
Garden Styles | City and Courtyard, Coastal Garden, Informal and Cottage |
By Danita Delimont, Shutterstock
While every effort has been made to describe these plants accurately, please keep in mind that height, bloom time, and color may differ in various climates. The description of these plants has been written based on numerous outside resources.
Requirements
Hardiness | 3
– 9 |
---|---|
Heat Zones | 1
– 9 |
Climate Zones | 1, 1A, 1B, 2, 2A, 2B, 3, 3A, 3B, 4, 5, 6, 7, 8, 9, 10, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 |
Plant Type | Perennials |
Plant Family | Iris - Other |
Exposure | Full Sun, Partial Sun |
Season of Interest |
Spring (Late) Summer (Early) |
Height | 1' – 2' (30cm – 60cm) |
Spread | 10" – 1' (25cm – 30cm) |
Spacing | 12" – 20" (30cm – 50cm) |
Water Needs | Average, High |
Maintenance | Low |
Soil Type | Loam |
Soil pH | Acid, Neutral |
Soil Drainage | Moist but Well-Drained, Moisture Retentive |
Characteristics | Showy |
Native Plants | United States, California, Midwest, Minnesota, Nebraska, North Dakota, South Dakota, Pacific Northwest, Idaho, Oregon, Washington, Rocky Mountains, Colorado, Montana, Utah, Wyoming, Southwest, Nevada, Arizona, New Mexico |
Tolerance | Deer, Wet Soil |
Attracts | Hummingbirds |
Garden Uses | Beds and Borders, Wall-Side Borders |
Garden Styles | City and Courtyard, Coastal Garden, Informal and Cottage |