Are Orchids Parasites? (How Do Orchids Grow?)

Orchid species vary greatly, some being rare and exquisite while others being more widespread.

One of the biggest misconceptions about the orchid is that orchids are parasites, but the relationship between an orchid and its host is far more complex.

Many people conclude that orchids are parasites because you’ll often see them clinging to the trees and bushes around them. But this is because an orchid is an epiphyte, not a parasite, meaning that they share a kind of symbiotic relationship with each other.

Continue reading to discover why parasites are epiphytes and what that means for both them and their hosts.

Are Orchids Parasites? 

No, most orchids are epiphytes, not parasites. The word epiphyte literally means “on top of plant” and describes the relationship between orchid and host. You can often see an orchid that has attached itself to the branches of a tree in the hope that it can absorb nutrients from the air and environment around them.

The key reason why orchids are not parasites is that they do not take anything from their host or cause it harm in any way. Instead, they use the host to get the things they need and can provide some of their own benefits in return.

Orchids that hang around on birch trees do not steal nutrients from the tree itself. Instead, they use their elevated position to access dead leaves, bird droppings, and other valuable elements of this environment. Meanwhile, the orchid can provide a few benefits to the tree, such as adding a shady patch or attracting wildlife.

Orchids are among the most resilient plants worldwide, so the idea that they are a parasite is a rather substantial misconception; these plants can survive in many environments and create all of their own nutrition.

Are All Orchids Epiphytes? 

Many orchids are epiphytes, but not all of them. Some species of orchids cannot photosynthesize their own food and thus rely on their host fungi to create the food instead. These orchids are parasitic and rely entirely on their host fungi to supply them with nutrients.

There are also orchids from the genus Corallorhiza, which we consider to be at least semi-parasitic as they feed from their tree hosts. However, this type of orchid is rare and only found in specific wild environments.

Why Aren’t Orchids Parasitic? 

A truly parasitic plant damages its host plant, a good example of which is mistletoe. When mistletoe attaches itself to a tree, the tree becomes its primary source of water and nutrients. Over time, this negatively impacts the tree’s ability to ward away other parasites or to deal with decay and wounds effectively, all of which can ultimately lead to its death.

Where orchids are concerned, the tale is not anywhere near as macabre. An orchid does attach itself to a host, but the tree is more of a place where the orchid can thrive, not a host from which to steal valuable nutrition.

Other orchid species, such as myrmecophytes, develop symbiotic relationships with ants to gain nutrition. The Coryanthes species take root in an ant nest where an accumulation of organic debris provides all the nutrition they require. 

The Schomburgkia tibicinis develop a large pseudobulb which hollows out as the plant matures. Once complete, an opening appears, and the orchid welcomes ants inside to build a nest. Here, the leaf litter can provide nutrition to the plant, while the ants protect the orchid from foraging insects.

The relationship between orchids and their hosts can be complex and intriguing, but the relationship benefits both parties in most circumstances. 

Where Do Orchids Get Their Nutrients?

Like many species of plants, orchids have many methods for obtaining the required nutrients. Many gain sustenance from organic matter, such as rotting leaves, that fall from the trees and plants in their surrounding environment.

Other orchids, such as those in the genus Catasetum develop a kind of “nest” around their base, consisting of masses of rigid, fine roots that trap organic debris, forming a sort of mini compost pile around the plant.

These methods are most prominent among the terrestrial species of orchid, which root into the earth and grow along the ground. But an epiphytes source of nutrition is somewhat different.

Epiphytes attach themselves to trees, as these species of orchid will grow above the ground and use the air for nutrition rather than soil. Plants that grow in this environment seek exposure to the sunlight, as they can gain far more plentiful amounts of nutrition from their elevated position.

Epiphyte orchids absorb nutrients from the air by using their roots. They also get all the carbon dioxide and moisture needed using the same method. The unique root system of this plant makes the most of humid environments, using a host to elevate it to the best position.

What Do Fungi Get From Orchids? 

Some orchid species share a symbiotic relationship with certain fungi called mycorrhizae; a relationship that is beneficial to both parties. Juvenile orchids will attach themselves to mycorrhizae to obtain carbohydrates; in return, they give the fungi moisture and the ability to obtain organic matter.

As many orchids grow in shaded environments, they struggle to obtain sufficient sunlight needed to produce chlorophyll. Instead, they rely on the help of their fungi. The fungi can digest organic matter and convert it into more simple molecules, like sugar, that provides nutrition to the orchid.

As the orchid grows, it may be able to sustain its own food source, though it will still turn to the fungi in times of hardship as a backup source of nutrition. And the fungi are happy to assist as the orchid continues to supply it with moisture and water.

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Summary

The answer to the question, “are orchids parasites?” is a resounding no. These hardy and resilient plants can make a home in some of the most remote places in the world thanks to their ability to gain nutrition from the air.

The common misconception of them being parasites stems from the fact that they will often grow on trees or bushes, but this is more of a symbiotic than parasitic relationship, and no harm comes to the other plant from the orchid residing there.

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