North America Native Plant

Western Tube Lichen

Botanical name: Hypogymnia occidentalis

USDA symbol: HYOC3

Habit: lichen

Native status: Native to North America  

Western Tube Lichen: The Fascinating Air Quality Indicator in Your Garden Have you ever noticed those strange, pale green crusty growths on tree bark and wondered what they are? Meet the western tube lichen (Hypogymnia occidentalis), a remarkable organism that’s neither plant nor animal, but something wonderfully unique that might ...

Western Tube Lichen: The Fascinating Air Quality Indicator in Your Garden

Have you ever noticed those strange, pale green crusty growths on tree bark and wondered what they are? Meet the western tube lichen (Hypogymnia occidentalis), a remarkable organism that’s neither plant nor animal, but something wonderfully unique that might already be calling your garden home.

What Exactly is Western Tube Lichen?

Western tube lichen is a fascinating composite organism made up of both fungi and algae living together in perfect harmony. This partnership, called symbiosis, allows lichens to thrive in places where neither partner could survive alone. The result is a resilient organism that looks almost otherworldly with its distinctive tube-like, inflated branches that create an intricate, coral-like appearance on tree bark.

This native North American species sports a pale gray-green color and forms distinctive hollow, tube-shaped lobes that branch out in interesting patterns. Unlike plants, lichens don’t have roots, stems, or leaves – they’re in a category all their own!

Where You’ll Find Western Tube Lichen

Western tube lichen is naturally found throughout western North America, with a particular fondness for the humid, coastal regions of the Pacific Northwest. You’ll typically spot it growing on the bark of various trees, especially conifers, where it forms distinctive patches that can range from small clusters to impressive colonies.

Is Western Tube Lichen Good for Your Garden?

Absolutely! While you can’t plant western tube lichen like you would a flower or shrub, having it naturally occur in your garden is actually a wonderful sign. Here’s why this lichen is a garden’s best friend:

  • Air quality indicator: Western tube lichen is sensitive to air pollution, so its presence means you have clean, healthy air in your garden
  • No harm to trees: Despite growing on bark, lichens don’t damage or parasitize their host trees
  • Unique aesthetic: Adds interesting texture and natural beauty to tree trunks
  • Low maintenance: Requires absolutely no care from you – nature handles everything
  • Year-round interest: Provides visual appeal throughout all seasons

How to Identify Western Tube Lichen

Spotting western tube lichen is easier once you know what to look for:

  • Look for pale gray-green, crusty growths on tree bark
  • Notice the distinctive hollow, tube-like branches that give it its name
  • Observe how the lobes are inflated and create a three-dimensional, coral-like appearance
  • Check that it’s growing directly on bark, not on the ground or rocks
  • Note that it’s typically found on the north or shaded sides of trees where moisture lingers

Creating Lichen-Friendly Conditions

While you can’t plant western tube lichen, you can create conditions that encourage its natural occurrence:

  • Maintain clean air: Avoid using pesticides and chemicals that pollute the air
  • Preserve mature trees: Lichens prefer established trees with textured bark
  • Ensure adequate moisture: Lichens thrive in areas with good humidity
  • Minimize disturbance: Let natural areas of your garden remain undisturbed
  • Avoid pressure washing: Don’t clean lichen off tree bark – it’s beneficial!

The Bottom Line

Western tube lichen isn’t something you’ll find at your local nursery, but if you’re lucky enough to have it naturally occurring in your garden, consider yourself blessed with a living air quality monitor. This fascinating organism adds unique beauty to your landscape while indicating that your garden environment is healthy and clean.

Instead of trying to remove lichens (please don’t!), celebrate their presence as a sign of your garden’s ecological health. They’re harmless to trees, require no maintenance, and provide year-round interest with their distinctive, otherworldly appearance. Sometimes the best garden additions are the ones that choose to live there naturally!

Western Tube Lichen

Classification

Group

Lichen

Kingdom

Fungi - Fungi

Subkingdom
Superdivision
Division

Ascomycota - Sac fungi

Subdivision
Class

Ascomycetes

Subclass
Order

Lecanorales

Family

Parmeliaceae F. Berchtold & J. Presl

Genus

Hypogymnia (Nyl.) Nyl. - tube lichen

Species

Hypogymnia occidentalis L. Pike - western tube lichen

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