North America Native Plant

Hernandez’s Bluecurls

Botanical name: Trichostema rubisepalum

USDA symbol: TRRU

Life cycle: annual

Habit: forb

Native status: Native to the lower 48 states  

Synonyms: Trichostema laxum A. Gray var. rubisepalum (Elmer) Jeps. (TRLAR)   

Hernandez’s Bluecurls: A Rare California Treasure Worth Protecting Meet Hernandez’s bluecurls (Trichostema rubisepalum), one of California’s most elusive native wildflowers. This petite annual herb might not be the showiest plant in your garden, but it carries significant conservation value and offers a unique opportunity for dedicated native plant enthusiasts to ...

Rare plant alert!

Region: Conservation status by state

Status: S3: Status is uncertain but is somewhere between the following rankings: 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 ⚘

Hernandez’s Bluecurls: A Rare California Treasure Worth Protecting

Meet Hernandez’s bluecurls (Trichostema rubisepalum), one of California’s most elusive native wildflowers. This petite annual herb might not be the showiest plant in your garden, but it carries significant conservation value and offers a unique opportunity for dedicated native plant enthusiasts to support biodiversity.

What Makes This Plant Special?

Hernandez’s bluecurls belongs to the mint family and showcases the delicate beauty typical of California’s native flora. As an annual forb, this herbaceous plant completes its entire life cycle in a single growing season, producing small blue flowers that give the species its charming common name.

The botanical name Trichostema rubisepalum may also appear in older references as Trichostema laxum var. rubisepalum, but don’t let the scientific terminology intimidate you – this is simply a reflection of how botanists have refined their understanding of this species over time.

A Rare California Endemic

This native wildflower calls only California home, making it a true Golden State original. However, its limited geographic distribution comes with an important conservation concern.

Important Conservation Note: Hernandez’s bluecurls carries a Global Conservation Status of S3, meaning it’s considered vulnerable to extinction. With only an estimated 21 to 100 occurrences and between 3,000 to 10,000 individuals remaining in the wild, this species needs our protection.

Should You Grow Hernandez’s Bluecurls?

If you’re passionate about California native plants and conservation, Hernandez’s bluecurls can be a meaningful addition to your garden – but with important caveats:

  • Only use responsibly sourced seeds or plants – Never collect from wild populations
  • Source from reputable native plant nurseries that grow from legally obtained, ethically sourced materials
  • Consider it a conservation project rather than a traditional garden plant
  • Perfect for dedicated native plant enthusiasts who want to support rare species preservation

Garden Role and Landscape Use

As a small annual forb, Hernandez’s bluecurls works best in:

  • Native California wildflower meadows
  • Specialized conservation gardens
  • Educational demonstration plots
  • Areas dedicated to rare plant preservation

Don’t expect this plant to be a garden workhorse or provide dramatic visual impact. Instead, think of it as a living piece of California’s natural heritage that you’re helping to preserve.

Growing Conditions and Care

While specific growing information for this rare species is limited, most California annual wildflowers in the Trichostema genus prefer:

  • Climate: Likely suited to USDA zones 9-10, matching its California distribution
  • Sunlight: Full sun exposure
  • Soil: Well-draining soils, possibly sandy or rocky
  • Water: Minimal summer water once established
  • Planting: Direct seed in fall for spring germination

Pollinator and Wildlife Value

While specific pollinator data isn’t available for this rare species, plants in the Trichostema genus typically attract small native bees and other beneficial insects. By growing Hernandez’s bluecurls, you’re potentially providing habitat for specialized pollinators that may depend on these native plants.

The Bottom Line

Hernandez’s bluecurls isn’t for every gardener, and that’s perfectly okay. This vulnerable species requires a conservation-minded approach and commitment to responsible sourcing. If you’re passionate about preserving California’s botanical heritage and can source seeds or plants ethically, growing this rare beauty can be a rewarding way to contribute to conservation efforts right in your own backyard.

For most gardeners interested in supporting California natives, consider starting with more common bluecurls species or other abundant native wildflowers. But for those ready to take on a conservation challenge, Hernandez’s bluecurls offers the unique opportunity to be a steward for one of California’s most vulnerable plant species.

Hernandez’s Bluecurls

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Asteridae

Order

Lamiales

Family

Lamiaceae Martinov - Mint family

Genus

Trichostema L. - bluecurls

Species

Trichostema rubisepalum Elmer - Hernandez's bluecurls

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