Epilobium ciliatum subsp. watsonii
(c) Joe Potter Butler, some rights reserved (CC BY), uploaded by Joe Potter Butler · licence
Family: Onagraceae · Type: Herb · Native
Epilobium ciliatum subsp. watsonii is a native California herb in the Onagraceae family, recognized by coastal habitat and robust size diagnostic.
Watson's willowherb is a California native perennial found in the northern and central Coast Ranges in moist coastal bluffs, streamsides, and disturbed sites at elevations below 200 meters. Flowering from May to October, this plant produces rose-purple to pink flowers 5 to 14 millimeters long in dense, flat-topped clusters. Growing robustly with well-developed rosettes and stems 30 to 150 centimeters tall, it spreads vigorously in wet environments. Its leaves are lanceolate to slightly ovate, with distal leaves that are not significantly reduced in size. The plant forms dense, leafy inflorescences that create a distinctive presence in coastal and streamside habitats.
Identification and appearance
Key characters: 10 sympatric species, coastal habitat and robust size diagnostic
Habitat and range
Habitat: Moist coastal bluffs, streamsides, +- disturbed sites
Elevation: < 200 m
California counties: Marin, San Francisco, San Mateo, Humboldt, Sonoma, San Luis Obispo, Santa Cruz, Del Norte, Mendocino, Monterey, Orange, Kern, Alameda, San Bernardino, Santa Barbara, Amador, Los Angeles, Nevada
Outside California: to British Columbia
Bloom period
Epilobium ciliatum subsp. watsonii blooms May-Oct.
How to tell it apart
vs Penstemon: Epilobium has 4 notched petals and opposite leaves; Penstemon has 5-lobed tubular flowers (snapdragon family).; vs Gambelia: Epilobium has 4 notched petals; Gambelia has 5-lobed tubular snapdragon-like flowers.; vs Fuchsia: Epilobium has notched petals spreading flat; Fuchsia has dangling tubular flowers with protruding stamens.; vs Keckiella: Epilobium has 4 notched petals; Keckiella has 5-lobed tubular snapdragon-like flowers.; vs Diplacus: Epilobium has 4 notched petals; Diplacus has 5-lobed tubular monkey flowers.
Frequently asked questions
Is Epilobium ciliatum subsp. watsonii native to California?
Yes. Epilobium ciliatum subsp. watsonii is native to California (recorded as native).
When does Epilobium ciliatum subsp. watsonii bloom?
Epilobium ciliatum subsp. watsonii blooms May-Oct.
Where in California does Epilobium ciliatum subsp. watsonii grow?
Epilobium ciliatum subsp. watsonii occurs in Marin, San Francisco, San Mateo, Humboldt, Sonoma, San Luis Obispo, Santa Cruz, Del Norte and other counties, at elevations of < 200 m.
What plant family does Epilobium ciliatum subsp. watsonii belong to?
Epilobium ciliatum subsp. watsonii is in the Onagraceae family, genus Epilobium.
What habitat does Epilobium ciliatum subsp. watsonii grow in?
Epilobium ciliatum subsp. watsonii grows in Moist coastal bluffs, streamsides, +- disturbed sites.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · Index of California Plant Names · CalPhotos
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.