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Dahlia help

williambonewilliambone Posts: 5
in Problem solving
Hey all

I've never came across this before in the years of growing dahlias, I've pulled them up and allowed them to dry, however there's a strange white/blackish growth appearing on the old stem of the dahlia.

It appears to be mould spores but I can't be certain, I have no idea what to do or how to fix this, so any help would be appreciated.
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Posts

  • bédébédé Posts: 3,095
    It looks like mould to me.  Sulphur dust used to be the accepted treatment, but I don't know whether that is up-to-date.
     location: Surrey Hills, England, ex-woodland acidic sand.
    "Have nothing in your garden that you don't know to be useful, or believe to be beautiful."
  • williambonewilliambone Posts: 5
    I'm not sure if that's available in the UK so I'll have a check and fingers crossed it works! 
  • FireFire Posts: 19,096
    edited October 2022
    Can you cut the mouldy bit off?  Make sure the tubers are dry and keep a close eye on them. The stems are hollow so can hold water. If in doubt, keep the tubers upside down for a while to make sure they are not holding onto damp. 
  • williambonewilliambone Posts: 5
    Yeah I previously cut off the stem which had the same stuff on it and thought I'd sorted it, unfortunately it still returns and I'm running out of stem to cut
  • FireFire Posts: 19,096
    I might be ok. If it gets totally dry then mould might not spread.
  • williambonewilliambone Posts: 5
    Sadly the dahlia never gets a chance to totally dry out before the mould takes hold ): I've been keeping it at bay by wiping it away but it keeps coming back, need something to kill it so I've bought some of that sulphur stuff and fingers crossed it works
  • FireFire Posts: 19,096
    You could try a little fungicide just on the end there. Where in the world are you based?
  • FairygirlFairygirl Posts: 55,117
    It looks as if you've cut the stems very close to the crown/tuber. That won't have helped.
    It's always better to leave a decent bit of stem if you're lifting the plants this early, then turn them upside down to let excess moisture drain away, so that it doesn't enter the tuber itself.  That helps prevent moisture sitting right at the crown where rot can start  :)
    It's a place where beautiful isn't enough of a word....



    I live in west central Scotland - not where that photo is...
  • FireFire Posts: 19,096
    I think the OP did have stem but tried to cut off the mould.
  • rossdriscoll13rossdriscoll13 Posts: 234
    @williambone you could try mixing a solution of 10% bleach and 90% water and dip the part that has mould on it in the solution.  Then lay the tuber on a piece of newspaper to dry.
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