Helianthus inexpectatus
Newhall sunflower
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Family: Asteraceae · Type: Perennial · Native
Conservation status: CNPS 1B.1
Helianthus inexpectatus (Newhall sunflower) is a native California perennial in the Asteraceae family, recognized by extremely limited to single known location.
Newhall sunflower is a rare (CNPS 1B.1) California native perennial found in the western Transverse Ranges along a single site near the Santa Clara River in Los Angeles County, growing in a spring-fed marsh within willow woodland at an elevation of 300 meters. Flowering from August to October, this plant produces yellow ray flowers with yellow disk centers in heads 2 to 2.5 centimeters wide, with 12 to 21 distinctive ray flowers extending 2 to 3 centimeters long. Growing with thick woody roots and a short rhizome, it reaches 1.5 to 5 meters tall with stems that are nearly smooth and glabrous. Its leaves are alternate or opposite, 10 to 20 centimeters long, lance-shaped with wedge-shaped bases and sharp tips, featuring strigose to short-rough hair on the lower surface. The fruit is 3 to 3.8 millimeters long with small pappus scales measuring 3 to 4 millimeters.
Identification and appearance
Key characters: 6 sympatric species; extremely limited to single known location
Habitat and range
Habitat: Spring-fed marsh in willow woodland
Elevation: 300 m
Bloom period
Helianthus inexpectatus blooms Aug-Oct.
Conservation status
CNPS 1B.1
How to tell it apart
vs Encelia: Helianthus is herbaceous with soft stems; Encelia is a woody shrub with persistent branches.; vs Bahiopsis: Helianthus has soft herbaceous stems; Bahiopsis is woody-based with persistent woody stems.; vs Wyethia: Helianthus has smaller disk flowers and readily falling seed scales; Wyethia has very large 8-12mm disk flowers.; vs Rudbeckia: Helianthus has a flat or rounded yellow center; Rudbeckia has a tall dark cone-shaped center.; vs Venegasia: Helianthus dies back to ground level; Venegasia is a large evergreen shrub in shaded canyons.
Frequently asked questions
Is Helianthus inexpectatus native to California?
Yes. Helianthus inexpectatus is native to California (recorded as native).
When does Helianthus inexpectatus bloom?
Helianthus inexpectatus blooms Aug-Oct.
What plant family does Helianthus inexpectatus belong to?
Helianthus inexpectatus is in the Asteraceae family, genus Helianthus.
Is Helianthus inexpectatus rare or endangered?
Helianthus inexpectatus carries California Rare Plant Rank 1B.1, state rank S1.
What habitat does Helianthus inexpectatus grow in?
Helianthus inexpectatus grows in Spring-fed marsh in willow woodland.
Related species
Other California species in the same genus, family, or bioregion.
- Helianthus niveus subsp. tephrodes — Algodones dunes sunflower
- Helianthus nuttallii — Nuttall's sunflower
- Helianthus nuttallii subsp. nuttallii — Nuttall's sunflower
- Helianthus nuttallii subsp. parishii — Los angeles sunflower
- Helianthus petiolaris — Prairie sunflower
- Helianthus petiolaris subsp. canescens
Sources: Jepson eFlora · CalPhotos · CDFW CNDDB
Last updated 2026-09-30
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.