Sick Peony Clump

northerner_on(Z5A ONCanada)May 23, 2011

Hello everyone:

To give you a little background, this particular clump of peonies is one of about 4 along a 30 foot bed that has been in place for over 28 years (when we arrived). They have always come up and bloomed and we cut them back in the fall, and this is the first time we have had any problems with them. Today as I approached this clump to weed and remove excess buds I relized that something was wrong as shown in this picture below.

Closer examination showed that the visible wilting, was due to a blackening along the effected stems as in the picture below:

The picture below is a close-up of some of these blackened areas. In some cases it was along several inches of the stem:

As you can see, this blackening extends along the stalks, I can't tell whether it moves up or down the stalks. I have removed all the effected stalks (13 in all) down to the green part of the stem. None of them was blackened to the root. Can anyone tell me what is wrong? I do not want this to spread to my other peony clumps (about 10) which I use extensively for bouquets. You may want to note that at the present, these clumps require a good weeding, and have grass and wild violets congesting their roots and stems. Thank you in advance.


P.S. I live in Ontario, Canada.

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I think you have a fungus problem, made worse by the bed full of weeds keeping it all wet and excluding air circulation. It is probably Botrytis paeoniae. I would weed and remove all affected stems, then I would spray only those plants now affected with a Bordeaux mixture, once more in about 10 days. The spray will discolor what ever it touches so be careful where you spray. Next fall I would at clean up time be very careful to clean the area of all plant material and then repeat the Bordeaux treatment. There are several fungicides you could use but I find Bordeaux has better lasting qualities. Al

    Bookmark   May 24, 2011 at 11:48AM
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northerner_on(Z5A ONCanada)

Hi Al, thanks for your diagnosis and solution. I have never heard of Bordeaux, but I will be going out of town to a Feed & Seed outfit who will certainly have it. I will have to do a bit of investigation into its toxicity etc. The reason for the weeds is that we have been legislated as pesticide-free: they are not readily available so I'll see what I can do. However, I will get in there and at least clean the clumps up. Thanks again.

    Bookmark   May 26, 2011 at 2:48AM
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You make your own Bordeaux and it is not banned anywhere that I ever heard of. Google and you will get the recipe and directions for use. Other than its turning everything blue, I know of no complaints. It is a mix of only copper and lime, but is a little tricky to mix, and does not store well. I only mix what I need and then clean the sprayer really well. Al

    Bookmark   May 26, 2011 at 9:26AM
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northerner_on(Z5A ONCanada)

That's great information, Al. I have located a recipe online and will have some made by tomorrow. I may have to hold off on spraying for a few days because it will be pouring rain for the next two days (as it was today). What rotten spring weather we have been having!!!

    Bookmark   May 28, 2011 at 1:23AM
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