What can be killing off my plants?

over the 18 months that we've been in this house, plants in the garden have been randomly dying off. At first I thought that they were getting too wet as it is quite a damp garden - it's actually an enclosed patio that seems to really hold on to water on the ground. But the latest one to go is my beloved Houttuynia cordata, which I bought specifically because it likes damp or boggy ground. 

The plant looks perfectly healthy, and then overnight a number of the leaves will turn brown, quickly followed by the rest of the plant. 

I asked a neighbour who gardens what she suggested, and she said she didn't know but that it was happening in her garden too, and in others in the local area. She thought it might be root beetle but when we pulled the dead plants up the roots were fine.

So far it's taken her monkey puzzle tree, a small confer I had, my three cosmos - one by one, although they were all in the same pot - and some rosemary and other herbs, so quite a range of plants.  

All of mine are in containers with fresh soil, so it can't be transmitted through the soil. Any ideas?



  • nutcutletnutcutlet Posts: 24,230

    Hello Donna

    Vine weevil is one of the biggest pot pests. Have you tipped out and checked for larvae?

  • AtillaAtilla Posts: 1,493

    I am thinking poor drainage as the only thing that Monkey Puzzle, Conifers, Rosemary and Cosmos have in common is water logged roots.

    I have not seen Vine weevil grubs attack any of those plants as they do not have the roots that they prefer - thick and soft like Begonia has.

  • Dave MorganDave Morgan Posts: 3,122

    Do the containers contain soil or compost Donna?

    You say that other people are suffering from the same problem, so where are their plants planted, in soil or in containers?

    How old is the house you are in?

    This may narrow it down a bit.

    As Nut says  vine weevil is the most likely culprit with compost, but if your containers are full of soil there may be another reason.

  • The containers have been filled with a general purpose compost. I've just realised that it's probably about time I started adding some plant feed in - could that be it? 

    Our house is a converted stable block, at least 100 years old. I'll ask the neighbours where their plants are planted as I only discovered the shared problem through a conversation (I haven't actually seen their gardens). 

    I found a few small snails on the houttynia when I went out to take a closer look this morning, could the be doing all the damage? 

    I use the same watering can for all the plants, so don't think it's a weedkiller problem. 

  • Stable blocks will have used very strong disinfectants over very long periods which may have built up in the soils which may be very toxic but this doesn't explain the containers.

    Do you know if you are troubled with cats and or foxes? animals urinating on plants will kill them if the plants are under stress from drought or waterlogging

  • Are you all perhaps using horse manure from a local stables, or compost that hasbeen made using it? Previous threads have discussed how modern Pyalid herbicides used in fields, and ultimately ending up in hay and straw, have caused wholesale damage to crops?

  • Dave MorganDave Morgan Posts: 3,122

    Verdun is right I do the same thing with my watering cans. keep them separate at all costs.

    Fox urine is particularly potent so if a dog fox is marking its territory you will have problems, only way to stop that is to get the old man to pee on it first at regular intervals (not into the pot of course just near it).

    The final answer may be human interference.

  • DovefromaboveDovefromabove Central Norfolk UKPosts: 43,618

    Rosemary and many other herbs are mediterranean plants that may well have suffered because of soggy conditions.

    There are all sorts of conditions that will kill a potted conifer off, including under or over watering.

    Cosmos die down in the winter.   

    Houttuynia cordata are deciduous shrubby plants that lose their leaves and die right down in the winter.  http://plantfinder.sunset.com/plant-details.jsp?id=1477

    With the greatest of respect, I'm wondering if we might not be panicking a little bit here? image

    No-one knows if you've done your housework, but everyone knows if you've done your gardening !
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