Yellow oysters (Pleurotus citrinopileatus mushrooms) are a relatively new species of oyster mushroom that have been showing up in all kinds of mushroom hunting boards in the Midwest lately, so I thought it would be good to take a close look at them today. I'll cover their history and identification, invasive status, as well as some tips for harvesting and cooking.
I knew these mushrooms would start showing up sometime where I live, it was just a matter of time. There's plenty of theories and urban legends about their origin, but one thing we know for certain is that yellow oyster mushrooms are not native to North America.
Golden oyster mushrooms are native to the hardwood forests of eastern Russia and northern China, as well as Japan. They're a popular edible mushroom over there and take well to cultivation, so it's no surprise that mushroom cultivation companies started selling them to grocery stores, as well as in grow kits for people at home where their spores can fly with the wind and spread.
Habitat
Like other pleurotus species, golden oysters are wood-decomposing saprobes, meaning they digest dying, fallen, and damaged trees.
In Minnesota and Wisconsin, they start to fruit at the same time as morels, around the middle of May. They can grow with a number of different hosts, but at least where I live, they seem to exclusively prefer dead elms. Occasionally I've seen them on cherry.
Are golden oysters mushrooms invasive?
This is one of the big questions I've seen debated in the foraging community. Here's the story I've been told, and that most people will know.
As rumor has it (and it is just a rumor) a mushroom farm in Dubuque Iowa had a fire, and, over the next few years, the mushrooms began to travel north. At home cultivation of yellow oysters, especially outside, has probably contributed to their spread.
The term "invasive" can be used in a number of ways. While some disagree, and they haven't been legally recognized as invasive (as if it would do anything to stop them) I consider them invasive and describe them to others as such for a couple reasons.
First, the mushrooms aren't native, and they're consuming resources that other native mushrooms (pheasant backs, mica caps, and wild enoki) could use.
Saprobes that fruit like a pathogen
Secondly, and what I don't see discussed much, is their fruiting pattern. Like their cousins, golden oysters are decomposers. Unlike their cousins, their fruiting pattern more resembles a pathogenic fungus like honey mushrooms than their other oyster cousins. In short, they act like we'd expect an invasive mushroom would.
Impact on morels
As someone who hunts a lot of morels with elms, the preference of golden oysters for dead elm trees, which the mushrooms seem to consume whole, worries me. As these mushrooms spread throughout the Midwest, what will happen to the morels? I have a theory.
Morels grow with dead elms, but also with other dying and disturbed trees. The intensity of Dutch Elm Disease is still real, but each year we move farther away from the epicenter, so to speak, and the dead elms that used to produce many morels are becoming more quiet.
There's a critical period for morel production with elms from my experience. You're looking for elms that are dying and shedding their bark to get the most morels. As the trees continue to decompose, other mushrooms like Cerioporus squamosus (pheasant back) and mica caps start to show up, and the morels eventually leave. To clarify, the morels leave the tree, but not the area.
My theory, which is backed up by anecdotal evidence from a number of morel hunters in Minnesota and Wisconsin, is that the Midwestern Morels are gradually transitioning hosts from elms to green ash, which is being affected by the emerald ash borer. Some morel hunters are already taking the cue, and I know people that now exclusively hunt green ash in the Midwest, instead of elms.
If the morels are indeed transitioning hosts, the voracity that golden oyster mushrooms consume dead elm trees, many of which are past the perfect period for producing morels, would be a moot point. We morel hunters just need to start looking for dying ash trees, instead of elms.
Identification
Common white oyster mushrooms are easy to identify, and bright yellow oysters are even easier. Here's a few quick tips.
Golden oyster mushrooms
- Have a sunny, bright yellow to golden brown cap
- Have a noticeably depressed center on the cap with age that resembles a funnel.
- Often grow in massive quantities, with trees producing many fruiting bodies.
- The stems are noticeably curved or bent.
- Have a white spore print.
- Young growing mushrooms will often be in very tight clusters.
Harvesting
Invasive or not, these are delicious mushrooms with a sweet, nutty taste and good texture. The only issue, as with other oyster mushrooms, is getting them before the bugs do.
You are looking for very young mushrooms without bug holes in the stem. Cut them from the tree, inspect the stem, and keep them in large clusters when you can.
Cooking
These are a great wild mushroom for the table when young and bug free, with a mild, nutty flavor. You can use them in your favorite wild mushroom recipes, and they're just fine cooked until golden and slightly crispy with a little olive oil, butter and garlic, but, as they grow in clusters, my favorite recipe is oyster mushroom steaks.
Above: I like to cook clusters of oyster mushrooms whole.
To make oyster mushroom steaks, I cook whole, large clusters roughly 4-6 oz each in a pan until wilted, then cover them with a weight and cook until golden brown and delicious. They make a great mushroom meat substitute.
Related Posts
Oyster Mushroom Soup with Soba Noodles
References
Tracing the Naturalization of Golden Oyster Mushrooms in the United States
Andrew
Nice article. I found some of these beauties today in Northern Missouri. I consulted my mushroom books and found they were not native to the area. The information here confirmed I indeed have found the golden oyster, and of course, Dubuque's not far away as the spore flies.
Alan Bergo
Thanks Andrew. I mean, I don't seriously think it was only the Dubuque fire, if that was really a thing. The folklore is half the fun sometimes. There's so many people growing these outdoors in our area they're just going to be another local species.
Bob Franklin
Alan, I love your recipes. Can golden oysters be used in place of regular oysters in other recipes? Any suggestions? Mine are already cut up individually, ready to stir fry.
Alan Bergo
Hi Bob. Yes you can substitute golden oysters for just about any mushroom.
Thane Maxwell
I don’t know much about it, and am open to learning more, but to me it seems like a pretty big leap to say that they are basically pathogenic simply because they fruit really big. They don’t cause disease, they don’t kill living trees etc. They are certainly big non-native saprobes. I am not clear on what really defines “invasive”, but again, it seems like a leap to say that because they are big that means they are spreading aggressively and pushing out other species. Perhaps those things are both true but they are 2 different statements. Thoughts?
Alan Bergo
Thane, my exact words are "fruits like a pathogen" which, if you know anything about mushroom foraging and other pathogenic species (honey mushrooms are a great example) they definitely do. It’s just my opinion, and I’m referring to it in a casual sense.
That kind of fruiting is analogous to the way that non-native plants often appear. Our native species haven't aren't used to them, so they have trouble competing with them. As for invasive mushroom status, there isn't a fungal invasive status protocol that I know of. I think a lot of things are under-standardized.
OysterFungi
The rumor about the fire is just that it seems, a rumor! A false one at that. There is no evidence of any fire like that, let alone one that matches up with the timeline of spread for golden oysters. Instead, there is actual research out sequencing the fungi caught in the wild and comparing to banked sequences including sequences from growers who sell grow kits. What that research has found, in summary, is that golden oysters have multiple points of introduction around the midwest and north east.
Alan Bergo
Nothing new here, really.
Susan
Hello Chef
My comments speak to your concern about golden oysters in some manner threatening your ability to harvest morels around dead or dying elm trees. Morels grow from the ground - from the soil. They do not use the wood of the tree for nutrition, but the underground network of mycelium from which the mushroom fruiting body springs, does have a relationship with specific trees, such as Elms. Once the tree dies or begins to die, this relationship is disrupted, and the mushroom sends up more fruiting bodies. On the other hand, oysters grow from dead and decaying wood from which they take their nutrition. Consequently, there is no real competition between the two mushroom species. I hope you find this helpful in understanding the relationships that mushrooms have with each other and their environment. Thank you for detailing how are you prepare them, looks delicious!
Alan Bergo
Hi Susan, thanks for commenting. I’m aware, and I have to say my experience says otherwise as elms with other mushrooms on them seem to push morels out, and golden oysters will readily infect elms at the stage morels like, as well as after the bark has fully shed. Either way it’s kind of a moot point as morels are growing in great quantity with green ash now too from the Emerald Ash Borer. I’ve been enjoying oysters as a bonus when picking morels the last few years.
John Denk
I agree with Susan. She has her facts right. I've been picking Morels for decades, and I'm well-read on why they fruit heavily around dying and dead elms. They do not consume Elm tree wood and have no need for the dead tree to remain in place.
Morels are mycorrhizal partners with Elm trees. The Morel mycelium down in the ground sort of work as an extended root system for the tree, providing water and other stuff in the soil that the tree needs and the tree supplies food to the Morel organism down under the ground.
The morels fruit en masse when they stop receiving food from the Elm as it dies. It's sort of their last shot at reproducing before they can't survive in connection with the dead/dying tree. At the point we're talking about here, it makes no difference to the Morels if other mushrooms consume the whole tree.
Alan Bergo
Hi John, let me clarify a few things.
Of course morels are mycorrhizal and oysters are saprobic, that's not up for debate. The other thing that isn't up for debate is that golden oysters will infect and consume elm trees at any age. If there was, say, a pure grove of elm trees, and the golden oyster mushrooms infect half of them, morels aren't going to show up from that disturbance. We're not losing a specific amount of mushrooms as that isn't really quantifiable, what we're losing is the potential for them. Even though we can't count them, it is still a loss of mushrooms.
The giant old elms that still produce are getting fewer and farther between. What I suspect will happen is that there will still be morels with elms, of course, but, as is happening now in Western Wi, people will start picking them with other trees they've also traditionally grown with that haven't received as much attention in the Upper Midwest. Hickory, and especially green ash are good producers, and some old timers have switched to green ash completely now. Hope that clarifies may logic here, which I stand behind.
john E hockstadt
Can you dehydrate golden mushrooms?
Alan Bergo
Yes.
Andi
Yes, but if you do it indoors (as with a food dehydrator) be prepared for your home to smell like a fish market!
Alan Bergo
I can second that.
Quinton
As far as bugs go can't you just soak in warm salt water to take care of that?
Alan Bergo
If you’re harvesting mushrooms with bugs in them they should be dried. Mushrooms should never be soaked in salt water.
Jason
Can you expand on this? I’ve been told to put Morels in salt water to draw out bugs.
Alan Bergo
Soaking morels in salt water is a common-repeated piece of folk wisdom that drives me crazy. The mushrooms absorb too much water this way. It's ok to clean them by dipping and swishing in water, but not submerged, and definitely not with salt. If people are harvesting morels with bugs in them, they should be dehydrated.
Tony
Considering how prolific these are, how do you preserve them? Duxelles?
It would be great if you could wilt them and freeze them in steak form, but I don't know how well they'd keep that way.
Alan Bergo
That's a good point Tony. Yes, these make good duxelles. I'm going to add a note about preservation now that you mentioned it. I also steam them and freeze or sous vide and it works well.