Bloomipedia
Purple owl's-clover (Castilleja exserta)
Photo: Gail A Baker via iNaturalist · CC BY 4.0 · resized

Flower profile

Purple owl's-clover

Castilleja exserta

Purple owl's-clover (Castilleja exserta) is a flowering plant in the Orobanchaceae family, native in the lower 48 states, blooming mostly March–May across the U.S.

Native in the lower 48

Purple owl's-clover is a wildflower that USDA PLANTS lists as native in the lower 48 states. It's on our flower lists for 2 states, and across the U.S. it's most often seen in bloom in March–May.

5states where USDA records it
2Bloomipedia state lists include it
17,500U.S. sightings*

*iNaturalist research-grade observations, as of October 17, 2026.

On our lists for: Arizona, California

Quick look

Castilleja exserta is a species of plant in the genus Castilleja which includes the Indian paintbrushes. Its common names include purple owl's clover, escobita, and exserted Indian paintbrush.

  • It belongs to the Orobanchaceae family. iNaturalist
  • USDA PLANTS describes it as an herb (forb) with a annual life cycle. USDA PLANTS
  • USDA PLANTS lists it as native in the lower 48 states and records it in 5 states. USDA PLANTS
  • NatureServe lists it as native to California and Arizona. NatureServe
  • In California, most iNaturalist sightings of it in flower come in March–May. iNaturalist
  • In Arizona, most iNaturalist sightings of it in flower come in March–April. iNaturalist
  • iNaturalist has 15,302 research-grade sightings of it in California, ranking #45 among the 178 flowers on our California list. iNaturalist
  • iNaturalist has 2,193 research-grade sightings of it in Arizona, ranking #43 among the 132 flowers on our Arizona list. iNaturalist

When does it bloom?

Flowering records by month across the U.S. (iNaturalist research-grade observations marked “Flowering”) (2,766 records)
Bloom time in the 2 states whose Bloomipedia list includes it
StateTypePeak bloomSightings*
CaliforniaNativeMarch–May15,302
ArizonaNativeMarch–April2,193

Conservation status

Federal (U.S. ESA)
Not listed No U.S. Endangered Species Act listing in the USFWS ECOS database. USFWS ECOS
NatureServe global
G4 Apparently secure worldwide. NatureServe
California
Not listed Not on California state-listed endangered, threatened and rare plants (14 CCR § 670.2), per CDFW's CNDDB list (July 2026). NatureServe: SNR, not yet ranked in California. CNDDB listed plants (July 2026)
Arizona
Not listed Not on Arizona Native Plant Law protected plants (Ariz. Admin. Code R3-3 Art. 11, App. A, eff. Feb. 2, 2025). NatureServe: SNR, not yet ranked in Arizona. AAC R3-3 App. A
Rare elsewhere
No other U.S. state ranks it S1, S2, SH or SX.

Checked October 17, 2026. Rankings and lists can change, so follow the links for the latest.

Can you eat it?

For peopleNot well documented

None of the sources we checked (NC State Extension (no page for this plant), USDA PLANTS) say whether it's edible or poisonous for people.

For petsNot well documented

It isn't on the ASPCA plant list.

🌿 Never eat a wild plant unless you're certain of its ID; this isn't medical advice. Worried about a person? Call Poison Control at 1-800-222-1222. Worried about a pet? Call your vet.

Where does it grow?

USDA PLANTS records purple owl's-clover in 5 states.

recorded by USDA PLANTS on our state lists not recorded

See the full list of states

Arizona, California, Hawaii, Massachusetts, New Mexico.

California counties with USDA records: Alameda, Amador, Butte, Calaveras, Colusa, Contra Costa, El Dorado, Fresno, Glenn, Humboldt, Inyo, Kern, Kings, Lake, Los Angeles, Madera, Marin, Mariposa, Mendocino, Merced, Monterey, Napa, Nevada, Orange, Placer, Riverside, Sacramento, San Benito, San Bernardino, San Diego, San Francisco, San Joaquin, San Luis Obispo, San Mateo, Santa Barbara, Santa Clara, Santa Cruz, Solano, Sonoma, Stanislaus, Sutter, Tehama, Tulare, Tuolumne, Ventura, Yolo.

Arizona counties with USDA records: Gila, Graham, Maricopa, Mohave, Pima, Pinal, Yavapai.

Names, range and relatives

Native status by region (USDA PLANTS): Hawaii: Introduced; Lower 48 states: Native.

County records: USDA PLANTS lists it in 56 counties across 5 states; the most are in California (46), Arizona (7), Hawaii (1).

Other Castilleja on Bloomipedia (11): Texas paintbrush, Felt paintbrush, Giant red paintbrush, Desert paintbrush, Wholeleaf paintbrush, Wyoming paintbrush, Painted-cup paintbrush, Rhexia-leaved paintbrush, Downy painted-cup, Northern paintbrush.

More from the Orobanchaceae family (24 on Bloomipedia; most observed first): Canadian lousewort, Warrior's plume, Elephant's-Head lousewort, Narrowleaf cow wheat, Sickletop lousewort, Florida bluehearts, Bracted lousewort, Dwarf lousewort.

More California flowers

Warrior's plume (Pedicularis densiflora)

Warrior's plume

Pedicularis densiflora

Native

🌼 Blooms in CA: January–April
Felt paintbrush (Castilleja foliolosa)

Felt paintbrush

Castilleja foliolosa

Native

🌼 Blooms in CA: February–May
California poppy (Eschscholzia californica)

California poppy

Eschscholzia californica

★ CA state flowerNative

🌼 Blooms in CA: March–May

Sources