White smelly fungus killing perennials



  • BorderlineBorderline Posts: 3,250
    Agree with what others said. Your soil looks too rich for Achilleas. They get like that in damp rich soils. 

    List all your plants or maybe photograph more plant combinations. It’s very likely some plants are not suitable in that soil, or there’s some over crowding that can be competing for space against less dominant plants. 

    The fungus growth is a separate issue most likely due to untreated wood used for the raised beds, but unlikely to be linked to your dying plants.
  • htyashtyas Posts: 6
    Thank you all.
    The sleepers were put in in 2017. I can only assume the landscaper used treated ones. 
    This particular bed was planted last summer, and there were no problems.
    It contains achillea, echinacea, and Kniphofia popsicle. The achillea was the first to go, followed echinacea. The Kniphofia appears to be coping despite the white stuff all around is base, and a few browning leaves.
    After the beds were first filled, the soil levels had sank a bit so before planting last year we topped up with compost, perhaps we overdid it.
    I’m not sure how to know if the drainage is good other than the fact the soil never waterlogs. But it was rainy at the start of summer. The landscaper has done a good job with drainage overall, and the garden it is not sat on clay (like our last one).
    The bed in which this is happening is identical to another one about 2 metres away also containing achillea and echinacea. That bed seems to be doing fine.
  • BorderlineBorderline Posts: 3,250
    Based on what you say and the plants you are growing I think you need to avoid making your soil so rich. Less feeding, use top soil or John Innes no 2 or 3 if you need to top up. 

    Identical planting schemes next to each other or opposite each other can sometimes perform differently so I would not immediately think the fungus is responsible unless everything is dying within a year. Kniphofia are quite tough plants. Can’t comment on Echinaceas but based on how I’ve seen them grow when I visit gardens and parks, they need to be grown in big groups in free draining soil. 
  • htyashtyas Posts: 6
    Okay, I think next spring, I’ll take out the plants and some soil; refill with topsoil; then replant and hope for the best!
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