Iris longipetala

Common Names

Coast Iris, Central Coast Iris, Long-Petaled Iris

Summary

Coast Iris is native to coastal California, a rhizomatous perennial that forms dense clumps with stems 30–60 cm tall and basal leaves 5–11 mm wide. It carries an inflorescence of 3–6 flowers that are lilac-purple with darker veining, outer sepals 6–10 cm long and petals 5–9 cm long, blooming from March to June in moist coastal prairie or open coastal forest at elevations below 600 m.

For cultivation, it thrives in moist, well-drained soils along the coast, tolerates heavy soils such as clay, and prefers full sun to partial shade with regular watering during bloom; once established, it is relatively drought-tolerant after flowering and deer-resistant. Propagation is by division, and it is well suited for landscape uses such as borders, pond margins, and bog gardens.

Lifecycle

Perennial

Height

12-24 inches

Spread

19.5-24 inches

Hardiness Zones

Zones 6-10

Sunlight Requirements

Full sun to partial shade

Soil Type

Moist, well-drained soil, preferably sandy loam

Soil Drainage

Well-drained soil

Soil pH

6.5-7.5

Bloom Color

Blue to lavender blue, white forms

Bloom Time

Spring

Foliage Color

Dark green

Fall Foliage Color

Gray, Yellow-brown

Leaf Lifecycle

Deciduous

Growth Rate

Moderate growth, 1-2 feet per year

Seasons of Interest

Spring and Summer

Propagation Methods

Seeds (no treatment), Division (rhizome division; two-fork method)

Attracts Wildlife

Attracts butterflies