Oyster Mushrooms

Shelling out – The Oyster mushroom

It’s good to know some mushrooms can appear all year round, especially when they’re edible and good. It’s nearly always the right time to look out for these beauties…

UK Oyster MushroomIn this case it’s the common and most welcome Oyster Mushroom (Pleurotus ostreatus). Usually growing in medium to large clusters on fallen logs, stumps or standing trunks, it’s one mushroom I always look out for during the ‘out of season‘ months. I mainly choose deciduous woods to visit (some can grow on coniferous wood) where they are most commonly found, especially on beech.

And thankfully they are also one of the most recognisable species out there. The distinctive ‘shell’ shapes and lateral (often minimal or missing) stems with white decurrent gills are all typical characteristics. The caps are convex shaped when young but will flatten out as they grow, often becoming wavy or split at the margin. And just to note: very rarely will you see a ’rounded’ shaped cap, but it does happen.

There is one thing though that the Oyster mushroom is not reliable with – and that is it’s colour (just like my spellchecker telling me I’ve spelt color wrong!). The shades are quite variable, but tend to be in subtle shaded hues of grey/whitish-brown, blue-grey, violet-grey etc. As you can see in these photos, I have stumbled across the grey-brown kind. A variant of the Oyster mushroom named Pleurotus columbinus is more or less the same mushroom but with a striking and beautiful violet cap. I haven’t seen any of those though. Shame.

As most of us all know, Oyster mushrooms are one of the most popular mushrooms to eat on the planet. There are many different species of course, successfully cultivated and sold throughout the world. But here in the UK, you’re best and most reliable bet is our common Pleurotus ostreatus. Cook ’em up in a stir fry one night and enjoy – Happy hunting.

Oyster mushrooms

Two separate encounters of the wild ‘shell shaped’ Oyster mushroom. Top: A group of young examples growing on a fallen log. Bottom: Very large and older examples (approx 14-15cm across) growing from a standing trunk.



6 – 20cm across. Shell shaped. Convex when young, flattening out. Often split or wavy margin. Subtle variable hues of grey-brown, whitish-brown, blue-grey, violet-grey. Flesh is born or blue-grey.


2-3cm x 10-20cm. Excentric to lateral or abscent. White with a woolly base.


Decurrent. Initially white fading yellowish later.
Spore Print: Pale lilac (see how to take a spore print here).


In medium to large clusters on stumps, fallen logs or standing trunks. Mostly deciduous trees such as birch. Sometimes on coniferous wood. All year round.


Edible and good.

The Genus PLEUROTUS (Oyster): Characteristics to look out for:

• Shell shaped fruting body with little or no visible stem.
• Growing on wood in clumps/dense groups
• Very decurrent gills.
• Spore print ranges from white to pale lilac.

19 replies
  1. Tom
    Tom says:

    Hi fellow mushroom fiends – i found some Oyster mushrooms next to a road (not a particularly busy road – average maybe) growing on a stump but dont know how risky they may be to eat what with the fumes/toxins etc..One mushroomer says best to leave alone but im not sure weather he’s maybe a bit overly-caucious ..thing is there’s loads and they look ace..are there many records of long-term illnesses from this type of thing?

    • J C Harris
      J C Harris says:

      Hi Tom
      An interesting and valid question. I too, get a little cautious when finding some great edible mushrooms next to the road. If the road is a busy one, I simply leave them. But if its a less busy road or street, I think it’s up to the individual to make the decision. I have eaten mushrooms found at the side of moderately busy roads and eaten them with no ill effect. I have heard no reports of long term illness or anything like that. Has anyone else? Just try a few of the mushrooms. You should be alright with that.

      All the best

  2. Tom
    Tom says:

    One mushroomer said ‘it’s likely that they’re full of pollution and also likely to have toxic metals in them, so probably not that edible.’ As you said tho i think maybe its just down to the individual too. I know a lot of people who eat berries/fruit from side of roads (including myself) so can’t see why mushrooms would be much different. There was something online i read about being careful about eating them next to roads/dump sites etc and that someone became very ill over the years from something mushroom related, but, i guess if you look hard enough you’ll always find a story or two about stuff like that and it all depends on other factors too… Thanks a lot, i may try and long as i dont eat too many i reckon i should be ok – quick reply too appreciated as they need eating soon ha.

  3. Tom
    Tom says:

    …oh, should i be at all cautious about them growing in May? – in my book it says mainly over winter for oysters but i guess it can just vary depending on the weather?..

  4. Lorna
    Lorna says:

    Hi there, I was delighted to come across a large crop of oyster mushrooms on a felled tree trunk in the park. I have only harvested white oysters in the past and these ones are light brown on top. They also have a bit more of a stem and a bit of a depression in the cap underneath the stem. In one of my mushroom books it says there are types of oyster mushrooms that should be avoided, and others don’t have any mention of this. What’s your experience of this? I tend to be over cautious and I’m sure have thrown out some perfectly good mushrooms in the past.

    • J C Harris
      J C Harris says:

      Hi Lorna. Sorry for delayed reply. The image link (below) shows some interesting pictures. I have not come across the likes of these. They do have characteristics of Oyster Mushrooms but the stems are exceptionally long, as you mentioned. I’ve looked through all my resources on Oysters but I can’t see any examples or reference to these. I was thinking they might be another species but the cap shape, spore print and gills riding down the stem like that are very ‘Oyster’ like. They may be a variant of some kind but I’m not fully sure. Sorry I can’t advise. Anyone else out there with experience finding mushrooms like these?

  5. Peri Cagirici
    Peri Cagirici says:

    I came across these huge mashrooms in my garden that fit the descriptions above. I am however, a bit frightened to eat them in case they are poisonous. I have taken some pictures of them but don’t know how to attach them on here.
    Please let me know if i can send the pictures for someone to identify the mushrooms for me whether or not they are safe to eat.

    Many thanks



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