How Do Plants Grow on Other Plants? The Science of Epiphytes

Quick Facts

What are Epiphytes?

Definition: Epiphytes are “air plants” that grow on the surface of other plants (usually trees) for physical support but do not take nutrients from them.

Key Difference: Unlike parasitic plants, epiphytes are harmless to their hosts; they make their own food through photosynthesis.

Common Examples: Orchids, bromeliads, Spanish moss, ferns, and many types of tropical mosses.

How They Survive: They have evolved specialized roots and scales to “drink” moisture directly from the air and rain.

Ecological Role: They act as “micro-habitats,” providing water and shelter for insects, frogs, and birds high in the forest canopy.

If you pause for a moment and actually look at the green world around you, yes, the plants-you’ll notice something strange. Not all plants follow the rules.

Some anchor themselves firmly into soil and grow into towering trees. Some stay small and quiet as herbs. A few even turn the tables and trap insects for food. And then there are the rebels of the plant kingdom: plants that spend their entire lives growing on other plants.

No soil. No roots in the ground. Just branches, trunks, and bark.

These “plants on plants” fall into two main groups: parasites and epiphytes. Parasitic plants like mistletoe and dodder, tap directly into their host for water and nutrients. They survive by taking.

Epiphytes, however, play a different game. They use other plants only as a place to live. No stealing. No harming. Just borrowing a bit of real estate high above the forest floor.

If you’ve ever looked up into the canopy of a tropical rainforest, you’ve probably seen them, orchids clinging to branches, ferns nestled in tree forks, moss carpeting bark. These are epiphytes: plants that have evolved clever adaptations to survive without ever touching soil.

So how do they get water? Where do they find nutrients? And why would a plant choose life in the treetops?

Let’s climb up and find out

Types of epiphytes: Vascular and non-vascular plants

Epiphytes are not just one kind of plant. In fact, they make up a huge and wonderfully diverse group. A simple way to understand them is to divide them into two categories: non-vascular epiphytes and vascular epiphytes.

Non-vascular epiphytes are the “simpler” plants of the bunch. They lack specialized tissues called xylem and phloem — the internal plumbing system that most plants use to move water and nutrients from roots to leaves. Without this transport system, these plants stay small and grow close to the surface they cling to, often forming soft mats rather than upright stems.

The most familiar example? Moss. That velvety green layer that coats tree trunks, rocks, walls, and other damp surfaces is often a non-vascular epiphyte. Moss belongs to a larger group called bryophytes, which also includes liverworts and hornworts. These plants may look simple, but they are remarkably good at absorbing moisture directly from rain, fog, and humid air.

Vascular epiphytes, on the other hand, do have specialized tissues for transporting water and nutrients. This allows them to grow larger, sturdier, and more structurally complex. Within this group, there are two main types: those that produce flowers and seeds, and those that reproduce using spores.

Ferns are the spore-producing vascular epiphytes. You can recognize them by their beautifully patterned leaves — and if you look closely at the undersides, you might spot rows of tiny brown dots. Those dots are clusters of spores, ready to begin the next generation.

Flowering epiphytes are often the show-stoppers. Orchids with their intricate blooms, bromeliads (relatives of the pineapple), and the ever-popular “air plants” all belong to this group. Many of these species are grown as ornamental plants because of their unusual shapes and vibrant colors.

How do epiphytes survive without soil?

Now that we know which plants live as epiphytes, the real question is: how do they survive without ever touching the ground?

Unlike most terrestrial plants, epiphytes don’t have access to soil — the usual source of water and nutrients. For typical plants, roots buried in the ground absorb water and minerals, which are then transported upward to help the plant make its own food using sunlight. Epiphytes, however, have had to solve this problem in a completely different way.

Instead of drawing resources from soil, epiphytes rely primarily on rainfall and moisture in the air.

Many vascular epiphytes have specialized leaves and roots covered in tiny hair-like structures called trichomes. These fine hairs help them absorb rainwater directly as it falls, as well as water vapor from humid air. In misty tropical forests, this atmospheric moisture can be a steady and reliable water source.

Their roots serve another important purpose: anchoring. Rather than digging downward, epiphytic roots wrap around tree trunks, wedge into bark crevices, and grow into small cavities. This allows the plant to cling securely to vertical surfaces high above the forest floor.

As for nutrients, epiphytes make the most of whatever collects around them. Bits of decomposing leaves, dust, bird droppings, and other organic debris gather in bark cracks and branch forks. Combined with dissolved minerals in rainwater, these materials provide just enough nourishment to sustain life in the treetops.

Through these clever adaptations, epiphytes turn what seems like a disadvantage — no soil — into an opportunity to thrive in places other plants cannot.

Do epiphytes harm their host trees?

At first glance, a tree covered in orchids, moss, and ferns might look like it’s under attack. After all, something is growing all over its trunk and branches. But in most cases, epiphytes are harmless tenants rather than destructive invaders.

Unlike parasitic plants, epiphytes do not tap into a tree’s tissues to steal water or nutrients. They simply use the tree as a place to live — a sturdy structure that lifts them closer to sunlight in crowded forests. Think of them as renters using the tree’s “real estate,” not its food supply.

That said, there can be exceptions. If an unusually large number of epiphytes accumulate on a tree, their added weight may strain branches. Dense growth can sometimes block sunlight from reaching the tree’s own leaves. However, in healthy forests, this balance is usually maintained naturally.

In fact, epiphytes often contribute to forest ecosystems by creating miniature habitats for insects, frogs, and even small mammals. What may look like clutter is actually part of a complex and thriving community high above the forest floor.

So while parasites harm their hosts, epiphytes mostly just share the space — quietly turning tree branches into entire living neighborhoods.

Comparison: Terrestrial vs. Epiphytic vs. Parasitic Plants

Feature	Terrestrial Plants	Epiphytic Plants	Parasitic Plants
Rooting Location	Roots grow in the ground (soil).	Roots attach to the surface of other plants.	Roots (haustoria) penetrate the host’s tissues.
Nutrient Source	Absorbed from soil via roots.	Absorbed from air, rain, and debris.	Stolen directly from the host plant’s “veins.”
Impact on Host	N/A (Independent).	Harmless; only use host for physical support.	Harmful; drains host of energy and water.
Key Examples	Oak Trees, Roses, Sunflowers.	Orchids, Bromeliads, Spanish Moss.	Mistletoe, Dodder, Ghost Pipe.
Primary Goal	Stability and nutrient access from earth.	Height to reach more sunlight and air.	Survival by exploiting another plant’s resources.

Why are epiphytes important to the ecosystem?

Though epiphytes might seem like just another group in the dizzying number of plant species out there, they perform many functions that are unique to them. Something you may not expect is that epiphytes are very important for many animal species that share their ecosystems. One way in which epiphytes help animals out is by providing them with habitats—a safe place to live, reproduce, and grow. The “tank bromeliads” found in South American forests, so called because of the large amounts of water that they collect between their leaves, are known to support entire ecosystems! Many species of insects, spiders, scorpions, worms, and even crabs make their homes in the pools of water these plants collect in the crooks of their leaves, living tucked away in the canopy. Even frogs and lizards use epiphytes, taking advantage of the cool microclimate provided by these plants to take shelter and lay their eggs. The stems, fruits, and leaves of epiphytes and the insects that live in them were also found to be an important source of food for many birds (Nadkarni, 1989).

Because they rely primarily on the atmosphere and rain for water and nutrients, epiphytes are especially sensitive to shifts in temperature, rainfall, humidity, and other changes in climate. It is for this reason that scientists are studying epiphytes to understand if and how climate change is impacting forests (Andama et al. 2003). If we lose epiphytes, we not only lose some very beautiful plants, but also the fascinating creatures that rely on them. It is for this reason that it is important to understand these plants better and increase awareness about them. So be sure to spread the word!

Examples of epiphytes you can find in nature

While many epiphytes thrive in tropical rainforests, they can be found in almost every environment—from damp temperate forests to arid deserts. Here are the most common groups:

1. Orchids (The Most Famous Epiphytes)

Orchids make up the largest group of epiphytic plants. Approximately 70% of all orchid species are epiphytes.

Where to find them: Tropical regions like the Amazon or Southeast Asia.
Key Feature: They often have thick, waxy leaves and “velamen” on their roots—a silvery coating that acts like a sponge to soak up rain instantly.

2. Bromeliads (Nature’s Water Tanks)

Related to the pineapple, these plants are famous for their rosette shape that forms a central “tank.”

Where to find them: Throughout the Americas, from Florida down to Argentina.
Key Feature: Their central reservoir can hold several liters of water, creating a tiny pond that supports insects and even tree frogs.

3. Ferns (The Ancient Survivors)

Many ferns have adapted to life in the canopy to escape the dark forest floor.

Common Examples: The Staghorn Fern (which looks like deer antlers) and the Bird’s Nest Fern.
Key Feature: They often grow in a circular pattern to “catch” falling leaves from the trees above, which decay and provide the fern with its own personal compost.

4. Mosses and Liverworts (The Green Carpets)

These are “non-vascular” epiphytes, meaning they don’t have a complex system to move water.

Where to find them: Cool, misty temperate rainforests (like the Pacific Northwest) and high-altitude “cloud forests.”
Key Feature: They are incredibly resilient and can lose nearly all their water during a dry spell, only to “wake up” and turn bright green within minutes of a rainfall.

5. Cacti (Surprising Air Plants)

Most people think of cacti in the desert sand, but some have moved into the trees!

Common Examples: The Christmas Cactus and the Queen of the Night.
Where to find them: Brazilian rainforests.
Key Feature: They have flat, leaf-like stems that are perfect for hanging off branches in humid environments.

Flesch Kincaid Grade Level: 11.1

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Glossary

Adaptation: The presence of specific features or certain habits which enable a plant or an animal to live in its surroundings

Humid: Containing a high amount of water or water vapor

Microclimate: The climate of a very small or restricted area, especially when it differs from the climate of the surrounding area.

Bryophytes: A group of non-vascular plants, that is, plants that lack the xylem and phloem networks that allow vascular plants to transport water and nutrients internally; includes mosses, liverworts, and hornworts

Rhizoids: Root-like structures on mosses