North America Native Plant

Pore Lichen

Botanical name: Pertusaria suboculata

USDA symbol: PESU18

Habit: lichen

Native status: Native to North America  

Discovering Pore Lichen: A Natural Garden Indicator You Can’t Plant Have you ever noticed those crusty, whitish patches growing on the bark of your favorite oak or maple tree? Meet the pore lichen, scientifically known as Pertusaria suboculata – a fascinating organism that’s neither plant nor animal, but something wonderfully ...

Discovering Pore Lichen: A Natural Garden Indicator You Can’t Plant

Have you ever noticed those crusty, whitish patches growing on the bark of your favorite oak or maple tree? Meet the pore lichen, scientifically known as Pertusaria suboculata – a fascinating organism that’s neither plant nor animal, but something wonderfully unique that might already be calling your garden home.

What Exactly Is Pore Lichen?

Here’s where things get interesting: pore lichen isn’t actually a plant at all! It’s a lichen – a remarkable partnership between a fungus and algae working together in perfect harmony. This native North American species forms those distinctive crusty, pale gray to whitish patches you might spot on tree bark throughout eastern and southeastern United States.

The pore in its name comes from the tiny openings visible on its surface, which are actually reproductive structures called ostioles. Think of them as nature’s little breathing holes!

Is Pore Lichen Good for Your Garden?

Absolutely! While you can’t exactly plant pore lichen (more on that in a moment), having it appear naturally in your garden is actually a fantastic sign. Here’s why you should be thrilled to spot it:

  • Air quality indicator: Lichens are incredibly sensitive to air pollution, so their presence means you have clean, healthy air
  • Ecosystem health: They’re part of a balanced, mature ecosystem
  • No harm to trees: Despite growing on bark, they don’t damage or parasitize their host trees
  • Wildlife value: Some birds use lichens for nesting materials

How to Identify Pore Lichen

Spotting pore lichen is easier than you might think once you know what to look for:

  • Appearance: Crusty, rough texture with a whitish to pale gray color
  • Location: Primarily on the bark of deciduous trees, especially oaks and maples
  • Texture: Feels rough and crusty to the touch, firmly attached to the bark
  • Size: Forms patches that can range from a few inches to several feet across
  • Pores: Look closely for tiny dark spots or openings on the surface

The Growing Reality: You Can’t Plant It

Here’s the quirky truth about pore lichen – you can’t actually grow it! Unlike traditional garden plants, lichens can’t be planted, propagated, or cultivated in the conventional sense. They appear naturally when conditions are just right:

  • Clean air environment
  • Suitable host trees (mature deciduous trees work best)
  • Proper humidity and light conditions
  • Time – lots of it, as lichens grow incredibly slowly

Creating Lichen-Friendly Conditions

While you can’t plant pore lichen directly, you can create an environment where it might naturally establish:

  • Plant native trees: Mature oaks, maples, and other deciduous trees provide ideal surfaces
  • Avoid air pollution: Minimize chemical sprays and support clean air practices
  • Be patient: Lichens can take years or decades to establish naturally
  • Don’t disturb: If you find existing lichens, leave them be – they’re slow to recover from damage

A Living Testament to Your Garden’s Health

Think of pore lichen as nature’s seal of approval for your garden ecosystem. Its presence tells a story of clean air, mature trees, and a healthy environment that’s taken years to develop. While you can’t rush the process or force its appearance, you can take pride in knowing that when it does show up, you’ve created something special.

So the next time you’re wandering through your garden, take a moment to appreciate these remarkable organisms. They may not add colorful blooms or attract butterflies, but they’re quietly testament to the thriving, healthy ecosystem you’ve helped nurture – and that’s pretty amazing in itself!

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 suboculata Brodo & Dibben - 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