North America Native Plant

Treetrunk Fern

Botanical name: Anetium

USDA symbol: ANETI

Life cycle: perennial

Habit: forb

Native status: Native to Puerto Rico  

Treetrunk Fern: The Tiny Epiphyte That’s Big on Character Meet the treetrunk fern (Anetium), a delightfully diminutive fern that’s mastered the art of living life on the edge—literally! This small but mighty epiphyte has carved out its niche by growing directly on tree bark and rocky surfaces, creating living artwork ...

Treetrunk Fern: The Tiny Epiphyte That’s Big on Character

Meet the treetrunk fern (Anetium), a delightfully diminutive fern that’s mastered the art of living life on the edge—literally! This small but mighty epiphyte has carved out its niche by growing directly on tree bark and rocky surfaces, creating living artwork wherever it takes hold.

What Exactly Is a Treetrunk Fern?

The treetrunk fern belongs to a unique group of plants called epiphytes—nature’s ultimate freeloaders (in the best possible way). Unlike typical ferns that root in soil, these clever little plants have learned to make their homes on tree trunks, branches, and rock faces. They’re not parasites, mind you; they simply use their host as a convenient perch while gathering everything they need from the air and rain around them.

This perennial fern produces small, thick, leathery fronds that cluster together in charming little colonies. The fronds are specially adapted to withstand the challenging conditions of epiphytic life, storing water and nutrients more efficiently than their soil-dwelling cousins.

Where You’ll Find This Tropical Treasure

The treetrunk fern is native to Puerto Rico and other parts of the tropical Americas. In its natural habitat, you’ll spot it decorating the bark of trees in humid forests, creating natural tapestries of green along with other epiphytic companions like bromeliads and orchids.

Is the Treetrunk Fern Right for Your Garden?

If you’re gardening in USDA zones 10-12, the treetrunk fern can add a touch of tropical mystique to your landscape. Here’s what makes it special:

  • Perfect for creating authentic tropical garden vibes
  • Adds vertical interest to tree trunks and garden structures
  • Low-maintenance once established in the right conditions
  • Excellent conversation starter—guests will wonder how it grows without soil!

However, this little fern isn’t for everyone. It requires consistently high humidity and warm temperatures year-round, making it unsuitable for most temperate climates. If you live outside the tropical zone, you might consider it as a greenhouse or terrarium specimen instead.

How to Identify Treetrunk Fern

Spotting a treetrunk fern is like finding nature’s own living jewelry. Look for these telltale characteristics:

  • Small, thick, oval-shaped fronds that feel almost succulent-like
  • Fronds growing directly from tree bark or rock surfaces
  • Clustered growth pattern forming small colonies
  • Dark green coloration with a somewhat glossy appearance
  • No visible soil or traditional root system

Creating the Right Environment

If you’re lucky enough to live in a suitable climate, the treetrunk fern thrives in:

  • High humidity environments (think 60-80% humidity)
  • Filtered or indirect light—direct sun will quickly fry these delicate beauties
  • Consistent warmth with temperatures rarely dropping below 60°F
  • Good air circulation to prevent fungal issues

The most authentic way to grow treetrunk ferns is by mounting them on rough-barked trees or textured surfaces where they can establish naturally. They’ll gradually spread and create those gorgeous living murals that make tropical gardens so enchanting.

A Living Piece of Art

Whether you encounter treetrunk ferns in their native Puerto Rican forests or successfully cultivate them in your own tropical garden, these remarkable little plants remind us that nature always finds a way. They’ve turned what could be seen as a disadvantage—having no soil to call home—into their greatest strength, creating beauty in the most unexpected places.

For gardeners in suitable climates, the treetrunk fern offers a chance to participate in one of nature’s most elegant collaborations: the partnership between plant and tree that creates living art right in your backyard.

Treetrunk Fern

Classification

Group

Fern

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision
Division

Pteridophyta - Ferns

Subdivision
Class

Filicopsida

Subclass
Order

Polypodiales

Family

Vittariaceae Ching - Shoestring Fern family

Genus

Anetium Splitg. - treetrunk fern

Species

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