North America Native Plant

Shenandoah Pore Lichen

Botanical name: Pertusaria shenandoensis

USDA symbol: PESH2

Habit: lichen

Native status: Native to North America  

Discovering the Shenandoah Pore Lichen: A Hidden Garden Ally Ever noticed those crusty, colorful patches growing on tree bark in your garden and wondered what they were? You might be looking at lichens – and if you’re lucky enough to live in certain parts of North America, you could be ...

Discovering the Shenandoah Pore Lichen: A Hidden Garden Ally

Ever noticed those crusty, colorful patches growing on tree bark in your garden and wondered what they were? You might be looking at lichens – and if you’re lucky enough to live in certain parts of North America, you could be spotting the Shenandoah pore lichen (Pertusaria shenandoensis), a fascinating organism that’s doing more for your garden than you might realize.

What Exactly Is the Shenandoah Pore Lichen?

First things first – despite its name, this isn’t actually a plant at all! The Shenandoah pore lichen is what scientists call a composite organism, which is basically nature’s way of showing us that teamwork makes the dream work. It’s a partnership between a fungus and algae (or sometimes cyanobacteria), living together in perfect harmony on tree bark and other surfaces.

This particular lichen belongs to the Pertusaria genus, which are known as pore lichens because of the tiny pore-like openings in their fruiting bodies. The species name shenandoensis hints at its connection to the Shenandoah region, though specific distribution details remain somewhat mysterious in the scientific literature.

Where Does It Call Home?

The Shenandoah pore lichen is native to North America, though the exact extent of its range isn’t fully documented in readily available sources. As its name suggests, it likely has strong ties to the Shenandoah Valley region, but like many specialized lichen species, it may have a more limited distribution than common lichens.

Why Should Gardeners Care About Lichens?

Here’s where things get exciting for eco-conscious gardeners! While you can’t exactly plant lichens like you would a tomato or rose bush, having them naturally occur in your garden is actually a fantastic sign. Here’s why:

  • Air quality indicators: Lichens are like nature’s air quality monitors – they’re super sensitive to pollution, so their presence usually means you’ve got clean air
  • Ecosystem support: They provide food and nesting materials for various small creatures
  • Soil building: When lichens break down, they contribute to soil formation
  • Natural beauty: They add unique textures and subtle colors to tree bark and garden surfaces

How to Identify Shenandoah Pore Lichen

Spotting this particular lichen requires a bit of detective work, since it’s part of a genus that can be tricky to distinguish without close examination. Look for:

  • Crusty, patch-like growths on tree bark
  • Generally pale or grayish coloration (though this can vary)
  • Small, pore-like openings in the surface when mature
  • A relatively thick, crusty texture compared to leafy or branching lichens

Keep in mind that definitive identification often requires microscopic examination, so if you think you’ve found this species, consider reaching out to local naturalist groups or university extension services for confirmation.

Creating a Lichen-Friendly Garden

While you can’t plant lichens directly, you can certainly encourage them! Here’s how to roll out the welcome mat:

  • Reduce air pollution: Avoid using chemical pesticides and fertilizers when possible
  • Maintain mature trees: Lichens love established bark surfaces
  • Be patient: Lichens grow incredibly slowly, so give them time
  • Avoid disturbing existing lichens: They’re fragile and take years to reestablish if damaged

The Bottom Line

The Shenandoah pore lichen might not be the showstopper of your garden, but it’s certainly a sign of a healthy ecosystem. If you spot what you think might be this species, consider yourself lucky – you’re witnessing one of nature’s most successful partnerships in action. Remember, the best thing you can do for lichens is simply to let them be and maintain the clean, stable environment they need to thrive.

So next time you’re wandering through your garden, take a moment to appreciate these quiet, crusty collaborators. They’re proof that sometimes the most important garden residents are the ones you barely notice!

Shenandoah Pore Lichen

Classification

Group

Lichen

Kingdom

Fungi - Fungi

Subkingdom
Superdivision
Division

Ascomycota - Sac fungi

Subdivision
Class

Ascomycetes

Subclass
Order

Lecanorales

Family

Pertusariaceae Körb.

Genus

Pertusaria DC. - pore lichen

Species

Pertusaria shenandoensis Hale & Dibben - Shenandoah pore lichen

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