Pleurotus citrinopileatus, the golden oyster mushroom, is a problematic species. A delicious edible mushroom native to East Asia, it’s popular both as a wild foraged edible and as a domestically grown cultivated crop. It’s a healthy and tasty food, a traditional medicinal plant with potential pharmaceutical uses—and in many parts of the world it’s an invasive which causes problems for local ecosystems. We’ve never grown it ourselves, but as it’s also popular with mushroom gardeners we though we’d learn more. So please join us as we dig in and learn a bit more about Pleurotus citrinopileatus and how it interacts with both humans and the environment around it.
The Origins and Uses of Golden Oyster Mushrooms
Along with its close relatives P. cornucopiae and P. ostreatus, golden oyster mushrooms are popular across Europe and Asia. Like other members of its family, P. citrinopileatus grows natively in hardwood forests, most commonly on dead oak, beech, and elm trees. The fruiting bodies of these mushrooms appear most aggressively in the autumn of the year, with distinctive bright yellow or golden-brown caps. The caps have a velvety texture and may be anywhere between three-quarters of an inch and four inches/2-10 cm wide, with white stems.
Golden oyster mushrooms can grow prolifically under the right circumstances, and combined with their delicate flavor and nutritional value as a great source of antioxidants they’re a popular food in eastern Russia, Japan, and parts of China. They’re also cultivated by both commercial growers and home gardeners or mushroom enthusiasts, which leads to the issues around P. citrinopileatus as an invasive species.
P. citrinopileatus an an Invasive Species
Golden oyster mushrooms are relatively easy to grow both at home and commercially. They can be cultivated via spore inoculations in a variety of growing media from coffee grounds to hardwood sawdust to straw bales. They’ve been grown deliberately in the US for at least 25 years at this point, but have been a recognized invasive species since at least 2012, per research done by a graduate student at the University of Wisconsin in 2018. She analyzed populations of golden oyster mushrooms in six states, and found that their genetic diversity indicated that the wild populations sprang from multiple sources and were in fact spread by humans. Since then, they’ve spread rapidly and have since established naturalized populations around the Great Lakes region of the US, in Washington State, and throughout the northeastern USA into southern New England and Vermont. In our research for this article we found informal reports of P. citrinopileatus in Ontario and Quebec, but we were unable to get official confirmation; if any of our Canadian readers know more please get in touch.
It’s tempting to ask “What’s the big deal?” Golden oyster mushroom are beautiful and tasty so why not enjoy having them around? The reality is that while P. citrinopileatus can be quite useful to humans, as an invasive species it can cause damaged to local ecosystem and overwhelm local mushroom and fungus populations. This disrupts local biodiversity and can have a cascading effect on other species which rely on native mushrooms.
Many states have been slow to take action about invasive populations of P. citrinopileatus. In some places it grows so abundantly as an invasive that it’s become a economically beneficial species, gathered by professional mushroom foragers and then sold at market. This can lead local and state officials to be reluctant to list golden oyster mushroom as an invasive and take steps to limit its spread.
What We Can Do
We’re not going to discourage home growers from cultivating P. citrinopileatus (or any other plant) but we would suggest being mindful in how we go about growing the plants we grow. Keeping careful controls on potential invasives is the responsible thing to do; growing them indoors or inside an enclosure/greenhouse can help limit spread, as can avoiding grown species that may be especially invasive in our particular location or environment. If we encounter golden oyster mushrooms in the wild, there are a number of other steps we can take. Logging them on an app like iNaturalist and then also notifying state and local authorities are good starting points; your local cooperative extension can help you find the right people to call. It might be ironic but gather and harvesting P. citrinopileatus before its spores drop can help limit its spread but again we should only harvest wild mushrooms with professional guidance and supervision to avoid accidentally harvesting a protected or poisonous species.
There are no bad plants, mushrooms, or animals, but there are organisms living in the wrong place For those of us in North America, P. citrinopileatus is one of these. It’s a beautiful and tasty mushroom that happens to cause problems when it grows where it shouldn’t. Humans are responsible for its introduction and spread, but we can also be part of the solution.
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