North America Native Plant

Trinity Mountain Rockcress

Botanical name: Arabis rigidissima var. demota

USDA symbol: ARRID

Life cycle: perennial

Habit: subshrub

Native status: Native to the lower 48 states  

Trinity Mountain Rockcress: A Rare Gem for Specialized Native Gardens Meet Trinity Mountain rockcress (Arabis rigidissima var. demota), a charming little perennial that’s about as exclusive as native plants get. This low-growing beauty is one of those special finds that makes dedicated native plant enthusiasts do a little happy dance ...

Rare plant alert!

Region: Conservation status by state

Status: S3T3Q: Status is uncertain but is somewhere between the following rankings: Uncertain taxonomy: ⚘ 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 ⚘ 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. ⚘

Trinity Mountain Rockcress: A Rare Gem for Specialized Native Gardens

Meet Trinity Mountain rockcress (Arabis rigidissima var. demota), a charming little perennial that’s about as exclusive as native plants get. This low-growing beauty is one of those special finds that makes dedicated native plant enthusiasts do a little happy dance – but it comes with some important considerations that every responsible gardener should know about.

What Makes Trinity Mountain Rockcress Special?

This petite perennial is a true native of the American West, calling California and Nevada home. As a member of the rockcress family, it stays refreshingly compact, typically growing under 1.5 feet tall and never exceeding 3 feet at maturity. Think of it as nature’s way of creating a perfectly sized plant for intimate garden spaces or specialized rock gardens.

Trinity Mountain rockcress grows naturally in California and Nevada, where it has adapted to specific environmental conditions that make it quite particular about where it will thrive.

The Rarity Factor: Why This Plant Needs Special Consideration

Here’s where things get interesting – and important. Trinity Mountain rockcress carries a Global Conservation Status of S3T3Q, which essentially means it’s uncommon enough to warrant careful attention. This isn’t your run-of-the-mill native plant that you can easily find at any nursery.

What this means for you as a gardener:

  • This plant should only be grown from responsibly sourced material
  • Never collect seeds or plants from wild populations
  • Work with reputable native plant nurseries that practice ethical propagation
  • Consider this plant only if you can provide the specialized care it likely requires

Is Trinity Mountain Rockcress Right for Your Garden?

The honest answer? Probably not for most gardeners – and that’s perfectly okay! This rare native is best suited for:

  • Experienced native plant gardeners who specialize in rare species
  • Rock gardens or alpine-style plantings
  • Conservation gardens focused on preserving rare California and Nevada natives
  • Gardeners in California or Nevada who can replicate its natural habitat conditions

Growing Considerations

Since Trinity Mountain rockcress is adapted to specific conditions in California and Nevada, it will likely require very particular growing conditions that mimic its native habitat. As a rockcress species, it probably prefers well-draining, rocky or sandy soils and may need protection from excessive moisture.

The challenge with rare plants like this one is that there’s limited cultivation information available, which means growing it successfully requires patience, observation, and probably some trial and error.

Better Alternatives for Most Gardens

If you’re drawn to the idea of growing a native rockcress but Trinity Mountain rockcress isn’t practical for your situation, consider these more widely available alternatives:

  • Other Arabis species that are more common and easier to source responsibly
  • Native wildflowers from your local region
  • Locally common rock garden natives that provide similar aesthetic appeal

The Bottom Line

Trinity Mountain rockcress is undoubtedly a fascinating native plant that deserves respect and conservation. However, its rarity means it’s not a casual garden choice. If you’re passionate about rare native plants and have experience with specialized growing conditions, it could be a worthy addition to a conservation-focused garden – but only when sourced responsibly.

For most gardeners, the best way to appreciate Trinity Mountain rockcress is to support conservation efforts and choose more widely available native plants that can provide similar ecological benefits without the conservation concerns. Sometimes the most responsible way to love a rare plant is to admire it from afar and let the experts handle its cultivation and preservation.

Trinity Mountain Rockcress

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Dilleniidae

Order

Capparales

Family

Brassicaceae Burnett - Mustard family

Genus

Arabis L. - rockcress

Species

Arabis rigidissima Rollins - Trinity Mountain rockcress

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