In recently planted a David Austin “Heritage” shrub rose. A week or so later the leaves started to turn a bronze color. Now about a month later the leaves look diseased. The other roses planted at the same time have not been affected. Can you tell me what may be happening here? Thank you.
Thank you for contacting the Toronto master gardeners.
From what I can tell from your photo, the leaves of your rose appears to be suffering from black spot. Black spot is the most important disease of roses and one of the most common diseases found everywhere roses are grown. It is caused by a fungus, Diplocarpon rosae, which infects the leaves and greatly reduces plant vigour. This fungal disease causes purple-black spots on leaves that usually yellow and drop.
This disease does not kill the plant outright, but over time, the loss of leaves can weaken the plant making it more susceptible to other stresses and to winter damage.
Please refer to our post onBlack Spot on Rose Bush for detailed instructions on how to combat this fungal disease.
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