Iris longipetala
Coast iris, Coast Iris
(c) Katherine Scott, some rights reserved (CC BY) · licence
Family: Iridaceae · Type: Perennial · Native
Conservation status: CNPS 4.2
Iris longipetala (Coast iris) is a native California perennial in the Iridaceae family, recognized by large flowers and thick rhizomes diagnostic.
Coast iris is a native perennial found in central and northern California coastal regions, including the North Coast, Central Coast, and San Francisco Bay Area, in moist coastal prairies and open coastal forests at elevations below 600 meters. Flowering from March to June, this plant produces lilac-purple flowers with darker veining, measuring 6 to 10 centimeters across, with large obovate sepals and elliptic petals. Growing 30 to 60 centimeters tall with rarely branched stems emerging from a thick rhizome 10 to 25 millimeters in diameter, it has distinctive basal leaves 5 to 11 millimeters wide. Its leaves include 1 to 2 cauline bracts that extend along at least two-thirds of the stem length, with the lowest flower bracts positioned alternately and enclosing the perianth tube. The flower's style branches extend 35 to 43 millimeters long with 12 to 15 millimeter crests and two-lobed stigmas.
Identification and appearance
Key characters: 9 sympatric species; large flowers and thick rhizomes diagnostic
Habitat and range
Habitat: Moist, coastal prairie or open coastal forest
Elevation: < 600 m
California counties: Monterey, Sonoma, Solano, Glenn, Mendocino, San Benito, Marin, San Francisco, San Mateo, Santa Clara, Napa, Alameda, Contra Costa, Humboldt, Los Angeles, Mariposa, Santa Cruz
Bloom period
Iris longipetala blooms Mar-Jun.
Conservation status
CNPS 4.2
How to tell it apart
vs Dietes: Iris has broad petal-like style branches; Dietes has thread-like styles and flowers lasting only one day.; vs Canna: Iris has six-parted flowers with drooping sepals; Canna has asymmetric flowers with one petal-like stamen.; vs Hemerocallis: Iris has petal-like style branches opposite stamens; Hemerocallis has simple thread-like styles and six equal tepals.; vs Typha: Iris has showy six-parted flowers; Typha has dense brown cylindrical flower spikes (cattails).; vs Sisyrinchium: Iris has large flowers with drooping outer sepals; Sisyrinchium has small flat flowers with six equal tepals.
Frequently asked questions
Is Iris longipetala native to California?
Yes. Iris longipetala is native to California (recorded as native).
When does Iris longipetala bloom?
Iris longipetala blooms Mar-Jun.
Where in California does Iris longipetala grow?
Iris longipetala occurs in Monterey, Sonoma, Solano, Glenn, Mendocino, San Benito, Marin, San Francisco and other counties, at elevations of < 600 m.
What plant family does Iris longipetala belong to?
Iris longipetala is in the Iridaceae family, genus Iris.
Is Iris longipetala rare or endangered?
Iris longipetala carries California Rare Plant Rank 4.2, state rank S3.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CNPS Rare Plant Inventory · Index of California Plant Names · CalPhotos · CDFW CNDDB
Last updated 2026-10-06
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.