how to treat hydrangea Powdery Mildew?

taniamelbourneApril 3, 2014

Hi everyone,

Im new to gardening. I bought hydrangea for 1 month already, last 2 weeks, it start moldy and got white dot on the leaves,i sprayed 'rose gun' which can treat powdery mildew, but I found it stop pruning.

Should I cut the leaves? but i dont want to cust all leaves... should I cut the flower as it stop purning?

BTW im from Melbourne and its autumn now.

Thanks everyone.

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as you can see it stop pruning. and the flower buds all turned red now...should I cut them so it can prune next year?

    Bookmark   April 4, 2014 at 7:28AM
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Remove the worst leaves. Spray with a fungicide for the other leaves including new leaves. Once moved outside you shouldn't have this problem. You can deadhead any spent blooms but don't cut too far into the old wood since that is where the next year's blooms will come from.

    Bookmark   April 4, 2014 at 8:48AM
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Thanks for your reply.

Now I moved it to outside under shade, but I think all the leaves got mildew... should I cut all the leaves? I sprayed for 2 weeks, and i dont think its getting better :(

And what do you mean by 'old wood' (sorry im pretty new to this), this is brand new hydrangea, and theres only 1 bloom, should i cut it?

    Bookmark   April 7, 2014 at 11:43PM
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Spraying affected leaves won't get rid of any visible spots but should stop any new spots from forming and protect new leaves. What did you spray with?

Old wood is the wood formed from the previous year(s). New wood or growth is the current year's growth. You can remove all the leaves if you find it unsightly. I have not done that to a mophead/lacecap (macrophylla) but I have done that to a paniculata and an oakleaf (quercifolia) with no adverse effects. The paniculata had spider mites or something else going on that looked so terrible I cut every leaf off in early summer - it completely filled out in a few weeks. The oakleaf had some kind of black spot going on but it was closer to fall so no new leaves came back which was kind of alarming but now it has all new leaves since spring is underway here.

    Bookmark   April 8, 2014 at 9:28AM
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