North America Native Plant

Boreal Orange Lichen

Botanical name: Caloplaca borealis

USDA symbol: CABO15

Habit: lichen

Native status: Native to North America  

Boreal Orange Lichen: A Tiny Splash of Color in Cold Climates If you’ve ever wandered through northern forests or rocky landscapes and spotted bright orange patches seemingly painted on rocks and tree bark, you’ve likely encountered the boreal orange lichen (Caloplaca borealis). This fascinating organism isn’t actually a plant at ...

Boreal Orange Lichen: A Tiny Splash of Color in Cold Climates

If you’ve ever wandered through northern forests or rocky landscapes and spotted bright orange patches seemingly painted on rocks and tree bark, you’ve likely encountered the boreal orange lichen (Caloplaca borealis). This fascinating organism isn’t actually a plant at all, but rather a remarkable partnership between fungi and algae that creates some of nature’s most vibrant natural artwork.

What Exactly Is Boreal Orange Lichen?

Caloplaca borealis belongs to the incredible world of lichens – composite organisms that result from a symbiotic relationship between fungi and photosynthetic partners like algae or cyanobacteria. Think of it as nature’s ultimate roommate situation: the fungus provides structure and protection, while the algae produces food through photosynthesis. Together, they create these eye-catching orange crusts that can brighten up even the gloomiest northern landscapes.

Where You’ll Find This Orange Wonder

True to its name, boreal orange lichen is native to the boreal and arctic regions of North America. You’ll spot it across northern Canada and the northern United States, where it thrives in the cool, clean air of these pristine environments. It’s particularly fond of exposed rock surfaces, but you might also find it decorating tree bark in undisturbed forests.

Identifying Boreal Orange Lichen

Spotting Caloplaca borealis is relatively straightforward once you know what to look for:

  • Bright orange to yellow-orange coloration that really pops against gray rocks
  • Crusty, flat appearance that looks almost painted onto surfaces
  • Small patches that may merge together to form larger colonies
  • Grows primarily on rocks, though occasionally found on bark
  • Most abundant in areas with clean air and minimal pollution

Is It Beneficial in Your Garden?

While you can’t exactly plant boreal orange lichen in your garden like you would a flower or shrub, its presence is actually a wonderful sign! Lichens are incredibly sensitive to air pollution, so finding them in your area indicates good air quality. They also play important ecological roles:

  • Act as natural air quality indicators
  • Contribute to soil formation by slowly breaking down rock surfaces
  • Provide food and nesting material for various small creatures
  • Add natural beauty and color to rock gardens and natural landscapes

Creating Lichen-Friendly Conditions

Rather than trying to cultivate lichens directly (which is nearly impossible), you can create conditions that might encourage their natural establishment:

  • Maintain clean air around your property by avoiding chemical sprays and pollution
  • Include natural rock features in your landscape design
  • Allow some areas to remain undisturbed and natural
  • Be patient – lichens grow extremely slowly, sometimes just millimeters per year

A Living Partnership Worth Protecting

Boreal orange lichen represents one of nature’s most successful partnerships, having survived and thrived for millions of years. While you might not be able to add it to your shopping cart at the garden center, appreciating and protecting these remarkable organisms helps maintain the health of our northern ecosystems. If you’re lucky enough to spot these bright orange patches in your outdoor adventures, take a moment to marvel at this incredible example of natural cooperation – and remember that their presence is a good sign for the environmental health of the area.

So next time you’re exploring rocky outcrops or northern forests, keep an eye out for these tiny splashes of orange. They might be small, but they’re playing a big role in the intricate web of life that makes our natural world so fascinating and beautiful.

Boreal Orange Lichen

Classification

Group

Lichen

Kingdom

Fungi - Fungi

Subkingdom
Superdivision
Division

Ascomycota - Sac fungi

Subdivision
Class

Ascomycetes

Subclass
Order

Teloschistales

Family

Teloschistaceae Zahlbr.

Genus

Caloplaca Th. Fr. - orange lichen

Species

Caloplaca borealis (Vain.) Poelt - boreal orange lichen

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