Slimy Fungus on gravel

Has anyone come across a slimy fungus which comes up through gravel drives. Brown on top green underneath. Looks like seaweed. Drys to very little in the sun but comes back immediately it rains. Have tried Pathclear and sodium chloride with no success.



  • Alina WAlina W Posts: 1,445

    Try spraying with a moss and algae killer, available at garden centres. That should get rid of it.

  • Thanks for that we'll give it a try. Need something quick as it is spreading faster than the triffids did! Anyone else actually got the stuff or know what it's called?

  • DovefromaboveDovefromabove Central Norfolk UKPosts: 42,843

    I think you've got a slime mould.  They usually grow on lawns but you must have some sort of organic matter in your gravel - leaves or something.  Google comes up with this advice

    Good luck.

    Gardening is cheaper than therapy, and you get tomatoes. 
  • Many thanks but don't think that's it. I've checked the website that has 23 pages of pictures of slime mouId and not one that looks like it. Also the stuff is growing out of 10 inches of hard core covered by 1 inch of scalpings with the nearest organic matter 5 metres away. It travels by being picked up on car tyres or on feet or being washed into new areas by heavy rain. The smallest bit then seems to grow wherever it falls - as long as it rains, which it's been doing a lot of!

    The best description is that it looks like seaweed after the tide has gone out - very wet and slimy. Would really appreciate hearing from anyone who has had experience of this. Thanks.


    Really would appreciate anyone contacting who has experience of this

  • DovefromaboveDovefromabove Central Norfolk UKPosts: 42,843

    Can you post a photo or two?  That might help.

    Gardening is cheaper than therapy, and you get tomatoes. 
  • Okay. I'll get it sorted by the end of the week. Thanks.



     Sorry about the delay. Yesterday after some hot sun it was completely dried to a crisp and blowing away in the wind. After literally two or three hours of rain it is now back again at full strength. It's really weird stuff. Size of fungus in picture is 60mm by 100 mm.

    Look forward to hearing your thoughts. If no one has ever come across this stuff should I be contacting Kew Gradens!! They can dig up the whole drive and take it away.



  • I have exactly this growing on a concrete path. It is a real pain and very slippery to walk on. I thought it was a slimemould but have been unable to identify the actual species- I agree with you it doesn't look like any of the pictures I can find on the 'net. I am scraping it off with a spade at the moment but if you find a better way to exterminate it I would be grateful to know.


  • I've now got some of the moss and algae killer recommended above so will try that as soon as the weather is okay. Have used rock salt quite thickly which seems to be having some effect - will need to see when it starts raining again.

  • yvonyvon Posts: 1

    I also have this stuff growing on the gravel in front of our house...I brought a sample of it to our local farm/hardwear/garden store and they are looking into it and coming back to me with hopefully a solution..will keep you posted...cant wait to get rid of it it is horrible...

  • Many thanks for that. We've now tried the following: Algae/moss killer (Patio Magic), Pathclear, Concentrated bleach, Rock salt, Mould and mildew killer with bleach, Dithane (fungicide), and Roundup. All of these were at double strength. NONE have killed it - you might like to mention that to your local guys.

    Of the above, concentrated bleach was the best after covering it very thickly but it hasn't killed it. It definitely doesn't like being covered in a layer of rock salt but, again, didn't kill it. If we can't kill it, then spreading a layer of rock salt would be our best guess to try and, at least, reduce it.

    Good luck.

  • Hi,

    Quick update. I've found reference to this on RHS My Garden forum. It's under "Gardening, Pests and Diseases, Seaweed like sludge in lawn". It appears to be called Blue Green Algae Nostoc Commune. They don't say how to kill it so will post that question on their site.

  • I have the same algae shown in your photagraph spreading over an area of limestone hardstanding, like you say it is worse after rain going slimey and green, and dries to resemble sea weed, I have tried most weed killers and moss sprays, bleach and now have resorted to removing and trying to bag it up to burn, but the task is daunting.

    I am going to Bridgmeer Garden Centre Nantwich to see if there is someone who can give me an idea of how to destroy it.


  • I have the same algae growing in different places around my house. In gravel, on stone and in soil. I have also tried everything to get rid of it. The only way I can keep it under control is to remove it with a spade. But it always comes back. Thanks for your help in identifying what it is. I have been trying to find that out for the past year. Would be grateful for any new advice you may have on how to get rid of it all together. Thanks again

  • Hello all

    I have the same stuff on some mossy staddle stones and yesterday discovered it all across MIL's patio. Her algae has some very large pieces and also some small blackish bubbles. It is lethal to walk on and has covered her patio very quickly.

    Just as a thought - two weeks ago we sprayed her patio with Roundup to get rid of grasses and other weeds in the cracks. I suppose Roundup hasn't got something in it which has caused this?

    Phylis Bide

  • Has anyone any ideas on eradicating this horrible stuff?

  • Many thanks for that. Could I ask for an update perhaps in, say, one month. That would be brilliant.



  • Is there any update on this?  We also have it spreading across the drive and we are about to try a flamethrower on it to try and burn it off!


  • was so pleased to find this identified as am despairing about it, but will now try the MMC-Pro mentioned

  • WaterdogWaterdog Posts: 1

    We have same thing going on the garden paths. We just found the stuff this spring . I want to kill it now !

    Thank you  

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