White smelly fungus killing perennials

htyas

Help!
Since late spring we’ve had a white smelly fungus killing the perennials stem by stem. It smells like nothing else! It appears on the surface of the soil and is also in the wooden sleepers making up the raised beds. Just recently the fungus on the sleepers has started growing into plaque-like growths rather than mushrooms. It appears in a few places in the garden but has so far taken perennials in just one bed as victims. They were achillea and echinacea. It is in the bed where the acer sits too but the acer seems so far unaffected. I’m also worried it’s spreading in the air in that a few other plants have a white powdery residue on them. 

Any advice how to get rid. I have no clue.
Thanks,
Helen

the enduring gardener

I agree with @Rik56 - it's probably just a timing thing and your perennials will come back fine in the new season.

htyas

I realise I’ve missed a few details out now. I’ve taken 3 perennials out because frankly there wasn’t much left of them. The die back was stem by stem. The roots were gone and covered in the smelly white stuff. This was how I first noticed the problem.
I guess it could be coincidence but it seems like it’s going from plant to plant killing each one as it goes. 

Here’s what the die back looked like 

amancalledgeorge

Worth telling us when did this occur...and maybe if you have any photos of the roots. The original photo and this new one look like deciduous plants going to sleep...of course a whole different ball game if that took place in August. 

htyas

I’ll check back though my photos but this started in early July, just as they were doing so well 

htyas

This photo was taken 10 July, and at this point I’d already removed two plants. I don’t have a pic of the roots. I’ve figured out I first noticed it on 8 June as the in-laws we’re visiting  at the time.

Dovefromabove

I do find achillea foliage goes brown very early. 

Buttercupdays

Was it just Achilleas? Does the bed have good drainage?

I ask because Achilleas hate wet soil and the roots could have rotted for that reason, giving the fungus a head start.

If it was other plants too, or the bed is well drained, we'll have to keep thinking!

edhelka

How old are your beds? Were the sleepers pressure treated? It looks like they are rotting.

Fungus usually attacks dead or decaying matter. It's perfectly possible that your plants died from a different reason and the fungus only colonised them afterwards. Over-watering or bad drainage could be a reason, it could also cause quicker rotting of your wood.

You could take the plants out, take the soil out, check the drainage and treat the wood.

Topbird

Are these plants all in one raised bed surrounded by sleepers?

If so, what did you use to fill the beds? If you've used something like a really rich manure-based mix it could be that the soil is too rich and poorly draining for the plants you've tried to grow.

How long have the plants been in? What sort of summer did you have (wet or dry?)

I'm wondering if there's too much  manure / spent mushroom compost been used? That can produce a funny smelling mould and is probably not suitable for echinacea and achillea unless very well mixed with lots of garden soil and grit.

A couple of years ago I bought in a truck load of 'soil improver' which was a mix of mushroom compost and farmyard manure. It was well dug into a new border but - from the smell of it and the 'burning' of some of the new plants - it was clearly not properly 'matured' before being sold. At least it was reasonably well 'diluted' with garden soil. Two years on everything is good and it's lovely soil.

Borderline

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.