Garden Forwardshrub
California lilac
Ceanothus thyrsiflorus
Growing guidance
Horticultural figures below are practitioner estimates for planning, pending expert review. The botanical record further down is sourced and verifiable.
Current-climate suitability
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Future-climate resilience
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Sun
Full sun
Soil moisture
free-draining, average
Heat tolerance
Up to about 42°C
Cold tolerance
Down to about -10°C
Waterlogging tolerance
1/5
Drought tolerance
5/5
Mature size
2–4 m tall, 3 m spread
Seasonal interest
Late spring · Blue
Maintenance
low
Wildlife supported
General wildlife value 4/5 (verified species relationships are shown only where structured data exists)
Known risks or warnings
Short-lived and resents summer watering or wet feet.
Toxicity: none
Verified botanical record
- Accepted scientific name
- Ceanothus thyrsiflorus Eschw.
- Family
- Rhamnaceae (Rosales)
- Rank and status
- species · accepted
- GBIF record
- Taxon 3039379
Ceanothus thyrsiflorus, known as blueblossom or blue blossom ceanothus, is an evergreen shrub in the buckthorn family Rhamnaceae that is endemic to Oregon and California in the US. The terms 'Californian lilac' and 'Mountain lilac' are also applied to this and other varieties of ceanothus, though it is not closely related to Syringa, the true lilac.
Description from Wikipedia — Ceanothus thyrsiflorus (CC BY-SA), shortened and unedited in substance.
Native status and geographic context
- United Kingdom: climate-suitable
- United States: native
- Australia: climate-suitable
Native status is never inferred from climate similarity. Plants restricted or invasive in a jurisdiction are excluded from recommendations there.
Demonstration data. Climate, plant and retailer records shown here are realistic samples awaiting horticultural validation and live data connections.