North America Native Plant

California Buckthorn

Botanical name: Frangula californica crassifolia

USDA symbol: FRCAC6

Life cycle: perennial

Habit: shrub

Native status: Native to the lower 48 states  

Synonyms: Rhamnus californica Eschsch. ssp. crassifolia (Jeps.) C.B. Wolf (RHCAC)  âš˜  Rhamnus tomentella Benth. ssp. crassifolia (Jeps.) J.O. Sawyer (RHTOC)   

California Buckthorn: A Native Shrub Worth Getting to Know If you’re looking to add a touch of California’s natural heritage to your garden, you might want to consider California buckthorn (Frangula californica crassifolia). This native shrub represents one of those quietly dependable plants that has been thriving in California’s landscapes ...

Rare plant alert!

Region: Conservation status by state

Status: S5T3?: Status is uncertain but is somewhere between the following rankings: Inexact rank: ⚘ Subspecies or variety is vulnerable: Either very rare and local throughout its range, found only in a restricted range (even if abundant at some locations), or factors are making it vulnerable to extinction. Typically 21 to 100 occurrences or between 3,000 and 10,000 individuals. ⚘ Secure: At very low or no risk of extinction in the jurisdiction due to a very extensive range, abundant populations or occurrences, with little to no concern from declines or threats. ⚘

California Buckthorn: A Native Shrub Worth Getting to Know

If you’re looking to add a touch of California’s natural heritage to your garden, you might want to consider California buckthorn (Frangula californica crassifolia). This native shrub represents one of those quietly dependable plants that has been thriving in California’s landscapes long before any of us started thinking about water-wise gardening.

What Exactly Is California Buckthorn?

California buckthorn is a perennial shrub that’s as California as it gets – it’s native to the Golden State and nowhere else in the country. You might also see this plant listed under its scientific synonyms Rhamnus californica ssp. crassifolia or Rhamnus tomentella ssp. crassifolia, which reflects some of the botanical name changes that happen as plant scientists learn more about species relationships.

As a true shrub, this plant typically grows as a multi-stemmed woody specimen, usually staying under 13 to 16 feet in height, though it can occasionally surprise you by growing taller or developing a single trunk under the right conditions.

Where Does It Call Home?

This buckthorn is exclusively a California native, making it a perfect choice if you’re trying to create a landscape that reflects the natural plant communities of the region. Its limited geographic distribution means it’s truly adapted to California’s unique climate conditions.

Why Consider California Buckthorn for Your Garden?

While specific information about this particular variety is limited in current resources, choosing native plants like California buckthorn comes with several potential advantages:

  • It’s naturally adapted to California’s climate patterns
  • Once established, native shrubs typically require less water than non-native alternatives
  • It supports local ecosystem health by providing habitat for native wildlife
  • It connects your garden to California’s natural heritage

The Reality Check: What We Don’t Know

Here’s where I need to be honest with you – detailed information about the specific growing requirements, wildlife benefits, and care instructions for Frangula californica crassifolia is surprisingly limited in current botanical and horticultural resources. This could mean a few things: it might be a less commonly cultivated variety, or it could be that most information focuses on the broader California buckthorn species group.

A Note About Rarity

This plant carries a Global Conservation Status of S5T3?, which indicates some uncertainty about its conservation ranking. While this doesn’t necessarily mean it’s endangered, it does suggest that if you’re interested in growing it, you should source your plants responsibly from reputable native plant nurseries that propagate their stock rather than wild-collect it.

Making the Decision

Should you plant California buckthorn? If you’re committed to native gardening and can find responsibly sourced plants, it could be a wonderful addition to a California native landscape. However, given the limited cultivation information available, you might want to:

  • Contact local native plant societies for growing advice
  • Check with California native plant nurseries about availability and care requirements
  • Consider it as part of a broader native plant garden where it can be grouped with other California natives
  • Be prepared for some trial and learning as you figure out its preferences in your specific location

The Bottom Line

California buckthorn represents the kind of plant that makes native gardening both exciting and challenging – it’s authentically local, potentially valuable for wildlife, and perfectly adapted to your region’s conditions. While we might not have all the growing details figured out yet, that’s part of the adventure of working with less common native plants. Just remember to source responsibly and perhaps start with one plant to see how it performs in your garden before committing to more.

Sometimes the most rewarding garden plants are the ones that require us to become better observers and more thoughtful gardeners – and California buckthorn might just be one of those plants.

California Buckthorn

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Rosidae

Order

Rhamnales

Family

Rhamnaceae Juss. - Buckthorn family

Genus

Frangula Mill. - buckthorn

Species

Frangula californica (Eschsch.) A. Gray - California buckthorn

Plant data source: USDA, NRCS 2025. The PLANTS Database. https://plants.usda.gov,. 2/25/2025. National Plant Data Team, Greensboro, NC USA