North America Native Plant

Crossidium Moss

Botanical name: Crossidium aberrans

USDA symbol: CRAB6

Habit: nonvascular

Native status: Native to North America  

Synonyms: Crossidium spatulaefolium Holz. & E.B. Bartram (CRSP8)   

Crossidium Moss: A Tiny Desert Survivor for Your Rock Garden Meet Crossidium moss (Crossidium aberrans), a remarkable little bryophyte that’s mastered the art of desert living. While most gardeners focus on flashy flowers and towering trees, this humble moss quietly demonstrates that sometimes the smallest plants can make the biggest ...

Crossidium Moss: A Tiny Desert Survivor for Your Rock Garden

Meet Crossidium moss (Crossidium aberrans), a remarkable little bryophyte that’s mastered the art of desert living. While most gardeners focus on flashy flowers and towering trees, this humble moss quietly demonstrates that sometimes the smallest plants can make the biggest impact in specialized garden settings.

What Exactly Is Crossidium Moss?

Crossidium moss is a terrestrial bryophyte—part of that fascinating group of plants that includes mosses, liverworts, and hornworts. Unlike the mosses you might find carpeting a shady forest floor, this little survivor has adapted to life in much harsher conditions. It’s herbaceous and has a particular fondness for attaching itself to rocks, dead wood, and other solid surfaces rather than settling into soil like many of its cousins.

You might occasionally see this moss referred to by its synonym, Crossidium spatulaefolium, but don’t let the scientific names intimidate you—it’s still the same tough little plant.

Where Does Crossidium Moss Call Home?

This native North American species has made itself at home primarily in the western regions of the continent, where it thrives in arid and semi-arid environments. You’ll typically find it clinging to rocks and other surfaces in desert and dry grassland areas.

Is Crossidium Moss Beneficial for Gardens?

While Crossidium moss won’t attract butterflies or produce showy blooms, it offers some unique benefits for the right type of garden:

  • Erosion control: Its dense, cushion-forming growth helps stabilize soil and prevent erosion on rocky slopes
  • Low-maintenance ground cover: Perfect for areas where traditional plants struggle
  • Authentic xerophytic landscaping: Adds genuine desert character to rock gardens and xeriscapes
  • Minimal water requirements: Ideal for drought-tolerant garden designs

Perfect Garden Settings

Crossidium moss isn’t for every garden, but it shines in specific situations:

  • Rock gardens with excellent drainage
  • Xerophytic or desert-themed landscapes
  • Areas with poor, rocky soil where other plants struggle
  • Spaces that receive full sun to partial shade
  • USDA hardiness zones 4-9

How to Identify Crossidium Moss

Spotting Crossidium moss requires a keen eye, as it forms small, dense cushions or mats. Look for these identifying features:

  • Tiny leaves arranged in a spiral pattern around the stem
  • Compact, cushion-like growth form
  • Attachment to rocks, wood, or other hard surfaces
  • Brownish-green to olive-green coloration
  • Very small size—individual plants are typically just a few millimeters tall

Encouraging Natural Establishment

Rather than trying to plant Crossidium moss in the traditional sense, you can encourage its natural establishment:

  • Create rocky areas with excellent drainage
  • Avoid overwatering—this moss prefers dry conditions
  • Provide surfaces like rocks or weathered wood for attachment
  • Be patient—moss establishment takes time
  • Avoid chemical fertilizers, which can harm bryophytes

A Word of Caution

While Crossidium moss isn’t invasive or noxious, remember that working with native bryophytes requires patience and realistic expectations. These plants establish slowly and may not provide the instant gratification that many gardeners seek. However, for those creating authentic desert landscapes or specialized rock gardens, this little moss can be a valuable addition that connects your garden to the broader North American landscape.

So next time you’re wandering through a rock garden or desert landscape, take a moment to appreciate the tiny but mighty Crossidium moss—proof that sometimes the most interesting plants come in the smallest packages.

Crossidium Moss

Classification

Group

Moss

Kingdom

Plantae - Plants

Subkingdom
Superdivision
Division

Bryophyta - Mosses

Subdivision

Musci

Class

Bryopsida - True mosses

Subclass

Bryidae

Order

Pottiales

Family

Pottiaceae Hampe

Genus

Crossidium Jur. - crossidium moss

Species

Crossidium aberrans Holz. & E.B. Bartram - crossidium moss

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