Is Growing Magic Mushrooms Bad for the Environment?

Recently, we’ve been reading some research on the spread of golden oysters (Pleurotus citrinopileatus) throughout the U.S. and Canada. We’ve been writing about golden oysters since around 2022, when we wrote the second edition of The Psilocybin Mushroom Bible (released last year), as it’s a great example of how well-meaning mushroom enthusiasm can cause serious ecological harm. Given our own mushroom advocacy — for psychedelic access, food sovereignty, and plain old deliciousness — we thought it would be worth expanding our views on the subject as a warning against the tendency of some of those in our community to spread mycelium everywhere with reckless abandon.

If you’re not familiar with the story of golden oysters, let us bring you up to speed. Golden oysters are an edible mushroom native to Russia, China, and Japan, but have spread outside their natural range to a number of countries in Africa, as well as the U.S. and Canada. In the case of the latter two countries, evidence suggests that golden oysters were introduced around 15 years ago in the Great Lakes region and have rapidly spread to 25 U.S. states and one province in Canada, as recent research from 2025 explains.

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Why Are Golden Oysters a Problem in North America?

Some species of plants, animals, or fungi that expand outside of their native range do little harm to the new environment they find themselves in, happily coexisting alongside everything else that lives there. We call these species “introduced“ or simply “non-native.” Once these species start harming their wider environment, for example, by outcompeting native species (sometimes to the point of extinction), they gain the label “invasive.“ Golden oysters fall into this latter category, as this year’s research found that every tree in which they were discovered housed only half or fewer other fungal species, such as mossy maze polypore or elm oyster. This is bad for a number of reasons:

1. Natural habitats are complex webs of living species, all of which depend on one another for coexistence. If you reduce the number of one or more native species, say through introducing a fast-growing non-native mushroom species, others, depending on the natives for food or shelter, can also suffer. If this happens on a large enough scale, ecosystems can become irreversibly changed.

2. A healthy ecosystem is usually biodiverse. Diversity in the ecological sense refers to the number of different species in a given ecosystem. If any species becomes too dominant, things like a chance disease can quickly run amok.

3. Some species that are outcompeted by invasive species can be useful to human health. Fungi, in particular, are of interest to biotech companies because their chemical compounds are relatively underexplored compared to plants —you wipe out these species and you wipe out the possibility that they might be turned into lifesaving drugs. As folks who appreciate nature for nature’s sake alone, we tend to agree with the late Bill Hicks: “Quit putting a goddamn dollar sign on every-fucking-thing on this planet.” However, there’s still a valid economic argument for protecting biodiversity.

Some argue that nature is in a constant state of flux and that terms like non-native and invasive are merely time-bound human constructs. However, this view is the biodiversity equivalent of climate change denial; the scientific consensus is that biodiversity is under significant threat, with some putting it in the top five threats to the natural world. An argument that we’re slightly more sympathetic to is how the discourse around invasive species, ecology, and conservation more generally has a weird colonialist framing to it. We could write a whole article exploring this idea, but our broadest view is that language aside, we shouldn’t throw the biodiversity baby out with the bad-vibe bathwater.

How Did Golden Oysters End Up in U.S. and Canadian Forests?

It’s not known exactly how golden oysters ended up far from their native range, but escaping commercial mushroom farms or deliberate introduction to wild forests by overzealous mycophiles are the two prime suspects. The evidence we have indicates that golden oysters were introduced simultaneously in many U.S. locations over a relatively short period. In the 1980s, few commercial strains were available, and cultivators did not especially favor them. Writing in Growing Gourmet and Medicinal Mushrooms in 1993, myco-entrepreneur Paul Stamets sings the virtues of golden oysters, stating that their “rarity and broad range of flavors make this species uniquely marketable and pleasurable to grow.” He also implicates himself a little:

“While travelling through China in 1983, I made clones of Chinese [golden oyster] mushrooms. Using a BIC™ lighter and a small scalpel, I inoculated 10 test-tube slants without the benefit of a laboratory. One of those clones survived the return trip.”

Though we’re not solely placing the blame for the golden oyster problem at Stamets’ feet, by his own account, he imported at least one strain of golden oysters in 1983 and then popularized them in what is now one of the most popular mushroom books of all time. It’s probably also worth noting that his mushroom grow kit business, Fungi Perfecti, was established in 1980, and still operates today under a different model —selling mycelium-based health products. In the same book, he also notes, in a somewhat detached way, for someone who operates a mushroom growing facility near one of the largest temperate rainforests in the U.S.:

“With the onset of commercial cultivation of these mushrooms adjacent to woodlands in North America, it will be interesting to see if these exotic varieties escape.”

To be fair to Stamets, there are no golden oyster escapes currently recorded anywhere along the U.S. West Coast, where Fungi Perfecti is based. He appears to have contained the golden oysters he had in the culture library at his own farm, even if his customers may have been less careful.

How Can We Address the Problem?

As of today, many of the big and small U.S. mushroom supply companies continue to sell golden oyster spores, spawn, and grow kits. This means that the number of deliberate or accidental releases will continue to grow in the coming years if no action is taken. Even if we do stop all sales of this invasive mushroom species today, the golden oysters currently taking over U.S. and Canadian forests act as a genetic wellspring that’s hard to prevent from spreading further. If you’re even slightly green-fingered, you’ll know how control measures struggle to stop similar botanical invasives like Himalayan balsam, Japanese knotweed, or kudzu. Add climate change into the mix, and previously inhospitable places for these species can — over the span of a few decades — become new sites of potential range expansion, and the problems that this brings in turn.

For golden oysters, the situation looks bleak. Reversing the clock might look like banning the sale of cultures and spores, whilst developing a genetic test to identify and remove infected trees from U.S. and Canadian forests. There’s a call for wild-foraged specimens to help with an ongoing research project, which is open until December 2025, but it might be worth trying to report and record any golden oyster you come across in the wild after the end of the year to help future research. If you don’t know how to do this, reach out to your local mycology club for help!

As mushroom cultivators, we should learn the lessons of golden oysters and other invasive fungi now, and apply precautionary principles to any new non-native fungi moving forward, including psychedelic ones.

Can Psychedelic Mushroom Cultivation Cause Similar Harm to the Environment?

As writers of a best-selling magic mushroom book, we don’t want to make the same mistake with shrooms that Stamets (at the very least) contributed to with golden oysters. We’re keen to teach others to grow their own magic mushrooms, but we’re also keenly aware of trying to mitigate any potential harm, be that to those consuming them or to the environment and indigenous cultures from which they originate.

Despite mycology currently being in the spotlight, the field of study has historically been neglected in favor of other disciplines, such as botany. This neglect is probably a contributing factor to why lists of invasive fungi tend to be much smaller than those of invasive plants. It’s not that fungi are uniquely less likely to be invasive, but more that there’s less known about them and fewer people qualified to study them. Thanks to heightened interest in fungi, this is starting to change, but the field is far less mature than botany. Mycology was only split out of botany into its own field in 1969, 11 years after Albert Hofmann isolated psilocybin from mushroom cultures collected in Mexico.

Add the legal status of psychedelic mushrooms to the backdrop of historical academic neglect of mycology, and the risk of undetected ecological harm gets plausibly higher. Unlike legal mushrooms, many research institutes won’t approve the budget to study psilocybin-containing mushrooms due to the legal and reputational risks that they bring. This makes the sustained, detailed study required to spot potential ecological harm caused by introduced psilocybin mushrooms arguably more difficult than that required for their legal counterparts.

Which Psychedelic Mushrooms Specifically Pose the Greatest Risk?

Without a rigorous study of all psychedelic species, it’s difficult to predict invasive risk with certainty. Even the current invasive species we’re aware of were often discovered long after they’d become embedded in ecologies outside their native range.

One of the most popular species of magic mushrooms is Psilocybe cubensis, which was first described in 1906 from a mushroom found in Cuba. However, due to its propagation through cattle dung, it now has a widespread distribution around subtropical regions around the world. This includes in regions where cattle were introduced, for example, in Australia. Though its precise country of origin is currently unknown, in Australia and elsewhere outside its natural range, it is considered non-native but not invasive. Due to Psilocybe cubensis’ preference for warmer temperatures, the places in the world where it can grow outdoors are relatively limited, which may limit its invasive potential. That’s not to say we shouldn’t be cautious, though, as new dung-loving Psilocybes are still being discovered to this day, such as Psilocybe ingeli in 2023 and Psilocybe maluti in 2021, both in South Africa. Taking advantage of naturalistic Psilocybe cubensis outdoor grows in suitable subtropical areas, especially where the local mycology has been less explored, could put you at risk of displacing yet-undiscovered native species!

What concerns us a little more are wood-loving Psilocybes, a name for a wide group of different species known collectively for their ability to grow on wood, typically in more temperate climates (in contrast to sub-tropical Psilocybe cubensis and other “dung lovers”). We’ve got a whole chapter on wood-loving Psilocybes in the second edition of our book, including how to grow them in natural or semi-natural settings. The advantages of growing these types of mushrooms have become especially apparent to us in recent years, in that you can cultivate mushroom patches away from your house and circumvent the legal risks associated with growing magic mushrooms at home.

Harm Reduction As An Ecological Concept

Despite the advantages of growing out in nature, we’ve been keen to encourage people to grow wood-loving Psilocybes, or any mushroom for that matter, only from native cultures. Due to the sheer range of wood-loving Psilocybe species adapted to different habitats, this is thankfully relatively easy to do in many areas of the world. However, we’ve also experienced firsthand the Pokémon-collector-like urge to grow as many different species as you can, especially as you get comfortable with basic techniques and want to find ways to keep your hobby interesting. However, if you combine this urge with an uncritical desire to spread magic mushrooms out into the wild, the chances of a non-native mushroom becoming invasive get a little higher.

We’ve seen this happen at least once with Psilocybe serbica. This European native species was introduced to the Pacific Northwest around 2012 by a couple of enthusiastic folks at the Shroomery. In the U.S., the Ohio Valley native Psilocybe ovoideocystidiata was described in 2003 as getting introduced to the west coast of America by one of the people who discovered it, and it’s now also found in Europe. One of the most well-known wood-lovers first described in Kew Botanical Gardens, England, in 1946 was Psilocybe cyanescens. We’re unsure of its origin, but some mycologists have suggested the first description might be of a non-native specimen, pointing to its likely origin on the west coast of the US and to its subsequent accidental transplantation to the U.K. botanical garden in the soil of imported plants. In some of these case studies, the introduction may have been deliberate, but the global sale of wood chips has probably encouraged their further spread. We’re not sure how much damage might have been caused in each case, but some psychedelic mushroom introductions into wild environments have clearly been going on for decades at this point. Due to a lack of study and legal issues, either no harm has been caused so far, or we don’t yet know about it.

Given the case study of golden oysters we’ve shared here, we really hope this generation of psychedelic mycologists doesn’t make the mistakes of Stamets’ generation, and approach this hobby with a little more ecological awareness and caution. Given the current climate crisis, we sure as hell need to tap into psychedelics’ profound potential for nature connection in a more proactive way than merely vibing out in the forest — and tread as lightly as we can on this earth.

This post is a syndication from “A Quickly Changing Kaleidoscope,” written by Dr. K. Mandrake and Virginia Haze, the authors of the critically acclaimed The Psilocybin Mushroom Bible and The Psilocybin Chef Cookbook.

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