Vail Lake Ceanothus / Center For Plant Conservation
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Plant Profile

Vail Lake Ceanothus (Ceanothus ophiochilus)

A close view of the pinkish-white flowers and small leaves of this species. Photo Credit: Dylan Hannon
  • Global Rank: G1 - Critically Imperiled
  • Legal Status: Federally Threatened
  • Family: Rhamnaceae
  • State: CA
  • Nature Serve ID: 129759
  • Lifeform: Shrub
  • Date Inducted in National Collection: 02/09/1992

This species was only recently discovered in 1989. This member of the buckthorn family (Rhamnaceae) has small, thick, narrow leaves and blue or lavender flowers. With its narrow leaves it can look similar to the very common Adenostoma fasciculatum when not in flower, perhaps explaining why it was only discovered relatively recently. It is only found on 20 acres near Vail Lake in Riverside County, California and it grows near an ancient volcano cone on soil rich in pyroxenite. This soil is extremely unusual and no other Ceanothus lives in it. Unfortunately, at the time of its discovery the site was owned by a developer and is still threatened by the potential for development.

Where is Vail Lake Ceanothus (Ceanothus ophiochilus) located in the wild?


Found on dry ridgetops and north to northeast facing slopes in chamise chaparral habitat. It occurs on shallow soils that were formed from phosphorus deficient material. (USFWS 1998)


Found in southwestern Riverside County, CA.

States & Provinces:

Vail Lake Ceanothus can be found in California

Which CPC Partners conserve Vail Lake Ceanothus (Ceanothus ophiochilus)?

CPC's Plant Sponsorship Program provides long term stewardship of rare plants in our National Collection. We are so grateful for all our donors who have made the Plant Sponsorship Program so successful. We are in the process of acknowledging all our wonderful plant sponsorship donors on our website. This is a work in progress and will be updated regularly.

Conservation Actions

  • 09/01/2020
  • Orthodox Seed Banking

Based on an September 2020 extract of the California Plant Rescue Database, California Botanic Garden holds 1 accessions of Ceanothus ophiochilus in orthodox seed collection. There are as many as 759 seeds of this species in their collection - although some may have been used for curation testing or sent to back up.

  • 08/30/2017

Development threatens the largest known population. Fire has the potential to eliminate or greatly set back this species--its true affects are as yet unknown. Hybridization with a common species of Ceanothus is another potential threat (CDFG 2002)

Nature Serve Biotics
  • 05/02/2017

Ceanothus ophiochilus is narrowly endemic to southwestern Riverside County, California, where it is restricted to nutrient poor soils. There are three populations known, with a total of about 7000-9000 individuals, some of them hybrids between this species and the locally common hoary-leaf ceanothus (C. crassifolius). All the populations are threatened by encroaching urban development, ensuing fire management, and less significantly, vandalism.

  • 01/01/2010

Found at three sites in Riverside county. One population contains 3,000 to 5,000 plants in privately owned land, and the other two exist on land managed by the Forest Service, and contain over 4,000 individuals total. (USFWS 1998)

  • 01/01/2010

The owner of the site has funded research by the county to determine how the use of fire could help or hurt the species. Also part of this research is a study to determine the risk of genetic swamping by hybridization with nearby common ceanothus species.

  • 01/01/2010

Two of the three known populations are protected, but the third (which happens to be the largest and most genetically pure) occurs on land that has repeatedly been proposed for development. A number of agencies have attempted to purchase the land where this population occurs, but have been unsuccessful for the last decade (CDFG 2002)

  • 01/01/2010

Reproductive studies to determine the impact of fire. Field surveys to determine if there are any other areas with the same pyroxinite soils or if there are other populations of the species.

  • 01/01/2010

Isoenzyme analysis to measure gene flow between this species and its more common neighbors. Transplantation experiments to determine if this species can grow in any other soil types.


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Taxon Ceanothus ophiochilus
Authority Boyd, Ross, & Arnseth
Family Rhamnaceae
CPC Number 13671
ITIS 506889
Duration Perennial
Common Names Vail Lake ceanothus
Associated Scientific Names Ceanothus ophiochilus
Distribution Found in southwestern Riverside County, CA.
State Rank
State State Rank
California S1
Ecological Relationships


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