Powdery mildew?

Question: We have 4 Dart’s Gold Ninebark bushes as a hedge, planted in June 2020. They are thriving, but one gets these diseased flowers, leaves and stems which turn a powdery grey  and in the winter eventually turn black. Come spring, i have trimmed out most of these dead leaves/branches, but the problem must be systemic because it keeps coming back. So far it has not spread to the other 3 bushes, but i worry it might, or that I will  eventually lose this bush. Is it powdery mildew, or something else, and how do I treat it to eliminate this problem? Please see attached photos

responder: Deb Kroon  Replied August 20, 2024, 7:10 PM EDT
response: Thank you for reaching out to ask2.extension. It’s starting as brown spot and then morphing into a mildew. Brown spots on ninebark leaves are often caused by fungal infections, which can lead to the leaves falling off the plant. Here are some ways to treat brown spots on ninebarks:  Use a fungicide.  Choose the right type of fungicide for the job. Protectant fungicides create a barrier, while systemic fungicides work from the inside to stop the infection. Some fungicides that can be used on ninebarks include: Liquid copper: A relatively safe organic fungicide that can help control powdery mildew, leaf spot, and early or late blight  Greencure: A safe product that can help control mildew on garden plants  Fung-onil: An all-purpose fungicide that can be used on many plants, including ninebarks  Baking soda: Mix 1 tablespoon of baking soda with a gallon of water and a splash of soap to create a homemade fungicide. Apply weekly to help the black spots fade Follow safety precautions: Wear safety gear when applying fungicides and follow the label's instructions carefully. Avoid misting the plants, as this can spread fungal spores to other leaves.  Rotate products: To prevent resistance, use different fungicides and rotate them.Rake up fallen leaves: Remove any fallen leaves to prevent the disease from spreading. Other factors that can contribute to brown spots on ninebark leaves include:  A combination of hot, dry weather and a fungal infection can cause problems;  Overwatering can suffocate the roots and create an environment for fungi to grow;   Water that pools around the roots can also lead to root rot. We’ve had a lot of rain this year, so that doesn’t help.  I would definitely treat the infected  shrub and keep an eye on the others. I hope this helps.

responder: The Question Asker Replied August 21, 2024, 9:27 AM EDT
response: Thank you for your informative response. I just have a couple of followup questions: Your directions caution one not to mist the plant so as not to spread spores. Then how does one apply the fungicides, most of which come in spray form? One certainly can’t “paint” each individual leaf! Also, should I be trimming out the branches that have already turned brown?Sent from my iPhone On Aug 20, 2024, at 6:10 PM, Ask Extension wrote:﻿

responder: Deb Kroon  Replied August 21, 2024, 5:27 PM EDT
response: As far as trimming, it would depend on how infected the bushes are.   I don’t know if you trim them back each year or not.  If you do then you could trim out the infection, especially the branches that have the  fuzzy fungus on them.  The spotted leaves could be treated as they haven’t progressed to far yet. As far as the fungicides,  you could try the systemic, which would be more of a longer term solution.  Yes you are right about misting.  I would spray them heavily, not using a light mist.  Drench the leaves.   Neem Oil is a fairly safe product to use.  Please follow directions.