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Hollyhock and rust

This year my Hollyhocks got a bad case of rust. Stems, foliage and flowers were affected. The best it could manage was the flower bud opening a little before the rust killed it.

I wanted to know if I should dig them up and get rid of them?

Last edited: 05 December 2016 23:15:47

Posts

  • RubyLeafRubyLeaf Posts: 260
    Edd says:

    Rust disease is caused by a fungal parasite. Unfortunately, there is no easy treatment for rust.

    Avoid wet areas and remove all infected parts and destroy them.

    Dust your plants with sulfur early next season to prevent infection and keep mild infections from spreading.

    Try any other methods that people on here provide. Garlic sprays with bicarbonate of soda will increase the alkalinity that will stop any fungal growth but too much will burn the plants.

    Best to ask a professional about chemicals (if you need to use them. I'm out of touch with the new stuff but I doubt it has changed ) They will charge you Unfortunately.image

    See original post

     Do garden centres sell garlic spray with bicarb in? Or am I supposed to mix it?

    What if the majority of the plant was infected? They're both still in the ground atm.

  • My experience is that if hollyhocks are infected with rust, there is nothing you can do to save them.  I had to give up growing them completely as no matter whether I grew from seed or bought plants, they always became infected in no time.  No difference in pots or ground.

    A trowel in the hand is worth a thousand lost under a bush.
  • RubyLeafRubyLeaf Posts: 260
    BobTheGardener says:

    My experience is that if hollyhocks are infected with rust, there is nothing you can do to save them.  I had to give up growing them completely as no matter whether I grew from seed or bought plants, they always became infected in no time.  No difference in pots or ground.

    See original post

     My Hollyhocks got infected in their 2nd year. But I really love the double variety and if I have to replace them every year I don't think thats so bad. The question I want an answer for is the ones in the ground that were infected. Will they have the disease next year?

  • Almost certainly, Rubyleaf.  Once a virus infects a plant, it will probably go down to the roots.  You could wait and see if the new leaves next year show any signs but the danger is that if they are still infected, it will likely spread to any new plants you grow.  To be safe, I would dig them up and dispose of them in your domestic waste - definitely don't put any part of them in a compost heap.

    A trowel in the hand is worth a thousand lost under a bush.
  • nutcutletnutcutlet Posts: 27,445

    rust never goes away, grow the hollyhocks behind something that hides the leaves.

    It's fungal, not a virus, fungal spores get everywhere. I've had hollyhocks get rust on the first true leaves from seed, in fresh compost, not near anything apparently suffering rust. Fungal spores are airborne.



    In the sticks near Peterborough
  • Thanks nut, I always thought it was viral rather than fungal!  Just looked up the offending fungus on the RHS site and see it affects several other plants in the family.  They say get rid of all other susceptible plants if hollyhocks are your main 'thing':

    https://www.rhs.org.uk/advice/profile?PID=564

    I might try them again one year but, like black spot infected roses, I hate the sight of diseased plants and don't have enough border space to hide the worst affected parts so will probably resign them to the list of ne'er do wells! image

    A trowel in the hand is worth a thousand lost under a bush.
  • nutcutletnutcutlet Posts: 27,445

    I've given them up really but I keep trying from time to time, they such fine plants (from a distance).

    I pass some on a frequent journey, never been closer than 20 foot or so, nowhere to stop if I wanted to. They look great.



    In the sticks near Peterborough
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