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iNaturalist — CC, credited & licensed per image
Rhamnaceae family
Sonoma Ceanothus Ceanothus sonomensis
Native
Early-season nectar — Flowers in a late-winter / early-spring window when few other plants in our catalog bloom — valuable early forage for pollinators (relative to our catalog's bloom coverage).
Sonoma Ceanothus is a perennial shrub native to the lower 48 states. It blooms Mar – Apr.
More about this plant
Ceanothus sonomensis, with the common name Sonoma ceanothus, is a rare species of shrub in the family Rhamnaceae. It is endemic to northern California. Wikipedia →
Growing & care
USDA PLANTS · TRY Conditions
Sources · Conditions
Cold hardiness (derived) — Hardiness
- Hardiness
- ≥ zone 11 derived from its U.S. range
Size & form
Sources · Size & form
USDA PLANTS — Lifespan
- Lifespan
- Perennial
In the garden
Shrub layer — Sits in the shrub of a layered food forest or polyculture.Open guide →
derived roles The garden year bloom → fruit → fall colour
J
F
M
A
M
J
J
A
S
O
N
D
Bloom
Bloom (the flower's colour)
Bloom · Mar – Apr — 15 obs · Herbarium specimens — Park et al. 2023 (CC BY 4.0)
Species characteristics from USDA PLANTS (public domain) + TRY (CC BY) — general guidance, not a
guarantee for your exact site. Deer "browsing" is documented palatability, not a deer-proof claim.
Wildlife & pollinators
How pollinator value is scored →❧ Caterpillar hosts ~45 caterpillar species
Ceanothus supports ~45 caterpillar species.
Native butterfly & moth caterpillars are the base of the terrestrial food web — most songbirds rear their young almost entirely on them. As a host for native Lepidoptera this is a strong genus.
Recorded feeding on Ceanothus in North America, including:
+ 8 more species → ↑ show fewer
Keystone count (genus-level) from Warren II 2026 (CC0) · Tallamy host-use records. Named species (a documented Nearctic sample, not exhaustive) from NHM HOSTS (CC0).
✦ Bees 1 bee visitor
1 native & managed bee species is documented visiting Sonoma Ceanothus :
Visitor records (observations, not exhaustive) from Noori et al. 2026 (CC BY 4.0) ·
GloBI →
Species thumbnails re-hosted from iNaturalist — Creative Commons, credited per image (hover for credit). Click any species to see it on iNaturalist. Not exhaustive; many taxa have no openly-licensed photo yet.
Related plants
More Ceanothus →
Native
Barranca Brush
Ceanothus verrucosus
●●●○○ 
Native
Bigpod Ceanothus
Ceanothus megacarpus
●●●○○ 
Native
Blueblossom
Ceanothus thyrsiflorus
●●●○○ 
Native
Buckbrush
Ceanothus cuneatus
●●●○○ 
Native
Calistoga Ceanothus
Ceanothus divergens
●●●○○ 
Native
Carmel Ceanothus
Ceanothus griseus
●●●○○ Same genus / family, ranked by ecological value — from the PlantKey catalog
Sources for this entry (16) Open & cited
[01] Scientific name & family — USDA PLANTS (DwCA, Zenodo 17903503)
[02] Growth habit & duration — USDA PLANTS (DwCA, Zenodo 17903503)
[03] Native status & distribution — USDA PLANTS (DwCA, Zenodo 17903503)
[04] Common name — USDA PLANTS (via GBIF)
[05] Invasive / introduced status — USDA PLANTS (DwCA, Zenodo 17903503) — native status
[06] Photos — iNaturalist — CC, credited per image
[07] Description — Wikipedia (CC BY-SA)
[08] Ecological value — Warren II 2026 (CC0) · Tallamy host-use counts
[09] Bloom period — Herbarium specimens — Park et al. 2023 (CC BY 4.0)
[10] Conservation rank — NatureServe Explorer (CC BY)
[11] Cold hardiness (derived) — Derived from U.S. range × USDA PHZM zones
[14] Caterpillar host count — Warren II 2026 (Dryad, CC0) · Tallamy host-use counts
[15] Caterpillar species — NHM HOSTS (CC0)
[16] County range — GBIF Open Data — open-licensed occurrences (CC0/CC-BY) → county
Spot an error or have a better photo? Every field links to its source, and the whole dataset is open.
Cite this page Open data, please attribute
PlantKey’s data is open under CC BY-SA 4.0 — free to reuse and adapt, with attribution and the same licence. Photos keep their own per-image licence + credit (see Sources above).
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