North America Native Plant

Glenwood Springs Rockcress

Botanical name: Arabis oxylobula

USDA symbol: AROX

Life cycle: perennial

Habit: forb

Native status: Native to the lower 48 states  

Synonyms: Boechera oxylobula (Greene) W.A. Weber (BOOX)   

Glenwood Springs Rockcress: A Rare Colorado Native Worth Protecting Meet Glenwood Springs rockcress (Arabis oxylobula), a little-known Colorado native that’s as special as it is scarce. This perennial forb might not be on every gardener’s wish list, but it deserves our attention—and our conservation efforts. What Makes This Plant Special? ...

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 ⚘

Glenwood Springs Rockcress: A Rare Colorado Native Worth Protecting

Meet Glenwood Springs rockcress (Arabis oxylobula), a little-known Colorado native that’s as special as it is scarce. This perennial forb might not be on every gardener’s wish list, but it deserves our attention—and our conservation efforts.

What Makes This Plant Special?

Glenwood Springs rockcress is a true Colorado endemic, found only within the borders of the Centennial State. As a member of the mustard family, this herbaceous perennial adds to Colorado’s incredible botanical diversity. You might also see it listed under its scientific synonym, Boechera oxylobula, in some plant databases.

Where Does It Call Home?

This rockcress has chosen Colorado as its exclusive home territory. Unlike many native plants that spread across multiple states, Glenwood Springs rockcress keeps its roots firmly planted in Colorado soil, making it a true state treasure.

A Word of Caution: Rarity Matters

Here’s where things get serious. Glenwood Springs rockcress carries a Global Conservation Status of S3, meaning it’s considered vulnerable. With only an estimated 21 to 100 occurrences and between 3,000 to 10,000 individuals remaining in the wild, this plant is walking a tightrope toward a more precarious future.

What does this mean for gardeners? If you’re lucky enough to encounter this plant or find it available through specialized native plant sources, proceed with extreme caution. Only consider planting it if you can verify that the material was responsibly sourced—never collected from wild populations.

Growing Glenwood Springs Rockcress

Given the limited information available about this rare species’ specific cultivation requirements, growing Glenwood Springs rockcress presents unique challenges. As a Colorado native, it’s likely adapted to:

  • High altitude conditions
  • Rocky, well-draining soils
  • Temperature fluctuations typical of mountain environments
  • Limited water availability

The Responsible Gardener’s Approach

While we can’t provide specific growing instructions due to limited horticultural information, we can offer some guidance for the conservation-minded gardener:

  • Source responsibly: Only obtain plants from reputable native plant nurseries that can guarantee propagated (not wild-collected) stock
  • Support conservation: Consider donating to organizations working to protect Colorado’s rare plants instead of trying to grow this species
  • Choose alternatives: Look for other Colorado native rockcresses that are more common and better suited to cultivation

Better Alternatives for Your Garden

Instead of risking harm to wild populations, consider these more common Colorado natives that can provide similar ecological benefits:

  • Common rockcress (Arabis drummondii)
  • Other Colorado native mustard family plants
  • Local wildflowers recommended by Colorado native plant societies

The Bottom Line

Glenwood Springs rockcress represents the delicate balance between our desire to grow native plants and our responsibility to protect rare species. While this Colorado endemic deserves our admiration and protection, it’s best appreciated in its natural habitat rather than in our gardens. By making thoughtful choices about which plants we grow, we can be stewards of biodiversity rather than contributors to its decline.

Sometimes the most loving thing we can do for a plant is simply let it be wild.

Glenwood Springs 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 oxylobula Greene - Glenwood Springs rockcress

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