Salix dieback due to waterlogging?

Discussion in 'Woody Plants' started by Souren, Oct 18, 2006.

  1. Souren

    Souren Member

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    Location:
    Hampshire, England
    Dear All

    I have a few questions about cause of death of and am seeking suggestions for replacing several mature dwarf broad-leaved Salix.

    I maintain a roof garden in Guildford in the South of England. This is a small water garden, with some concrete-edged planters holding fairly clayey soil overlain by a gravel mulch. The water table in the soil varies between 4 and 20 cm below surface.

    The Salix have been in the wet ground since 2000. In winter 2004/5, I pruned them back quite hard as they had become quite large. Beginning early summer 2005 they began to die back and get blackfly etc. They have now all died. I have heard that there is a virus attacking Salix, but don't have any specific information. I sent samples to RHS wisley but they did not find any evidence of virus (no clinical tests done).

    The conclusion, for lack of any other, is that the plants have eventually succumbed to waterlogging. Other plants which thrive in this garden are Phyllostachis, Miscanthus sinensis, Pennisetum, Darmera, Cyperus. There is a corkscrew willow which seems quite happy. Plants which are struggling but not dead yet are red-stemmed Cornus & Pinus mugo.

    Would anyone have any suggestions for replacement plants, ideally: evergreen shrub, able to be pruned to a round shape (similar to Box or Hebe), obviously tolerant of waterlogged conditions, moderately sheltered to fairly exposed aspect? Evergreen herbaceous would work as an alternative. Deciduous shrub would also work, if one comes to mind.

    I'd be very grateful to hear from you. Regards
    Souren
     
  2. Rima

    Rima Active Member

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    Hi - I'd say that if your willows are happy, it would be understandable that your mugos aren't, and the lilacs probably fall in the middle somewhere. A 'boggy' wet setting is inhospitable to ~ the majority of trees, if not perennial flowers, and evergreen conifers and many maples (as well as succulents, of course) would be the first to suffer. They need dry, gritty, sandy and sunny locations with fast drainage, and are acid lovers, though maples and lilacs are less so. The only evergreen shrubs that like water and might grow in too much clay would be yews, but I can't personally recommend planting anything in clay, to be honest.
     
  3. James D.

    James D. Active Member

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    you could try some types of illex, like ilex verticillata(american winterberry). They like a fair amount of water and are semi-evergreen here in canada and have the lovely red berries in the fall/winter if you get a male and a female plant.
     
  4. Souren

    Souren Member

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    thanks
     
  5. oscar

    oscar Active Member

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    i found this...
    willow anthracnose, caused by the fungus Marssonina salicicola. These diseases can be a serious problem on trees grown for timber or ornament.
    sorry but i havnt had time to read up on Marssonina salicicola....so it might not be the problem
     
  6. Souren

    Souren Member

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    Thanks, I'll look into it
     
  7. kalmia

    kalmia Active Member

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    Location:
    Hammond, Indiana, USA
    I would have guessed those would be alright in those wet conditions. I have seen red osier dogwood growing wild in damp, flooded locations in large thickets near me. I think I may have a picture somewhere of a large thicket.

    I'm not sure what to suggest if those didn't make it. I can see the mugo not making it, but I would think the others would.
     

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