As a peony enthusiast, I know how disheartening it can be to see those ugly black spots marring the beauty of your peony leaves. But don’t dismay! With some knowledge and preventative care, you can get those peonies looking gorgeous again.
What Causes Black Spots on Peonies?
There are a few main culprits when it comes to black spots on peony leaves
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Fungal diseases – The main offenders here are botrytis blight, phytophthora blight, and peony leaf blotch. These fungal diseases thrive in cool, damp conditions.
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Bacterial infections – Bacterial leaf spot can lead to small black lesions on leaves, High humidity encourages the spread of bacteria
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Viral diseases – Peony ringspot virus and tomato ringspot virus can cause distinct circular black marks on leaves,
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Environmental factors – Physical damage from wind, hail, insects, as well as issues like poor drainage or nutritional deficiencies.
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Pest damage – Insects like thrips can puncture leaves and leave behind black dot damage.
Preventing Black Spots on Your Peonies
An ounce of prevention is worth a pound of cure when it comes to peony black spot. Here are some tips to keep those leaves looking pristine:
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Choose disease-resistant peony varieties when possible. I adore the ‘Sarah Bernhardt’ cultivar for its resistance to botrytis blight.
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Avoid overhead watering, which spreads fungal and bacterial diseases. Instead, water at the base.
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Water early in the day so leaves have time to dry out before nightfall.
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Space peonies at least 3 feet apart to allow for ample air circulation.
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In fall, remove spent blooms and foliage to eliminate disease reservoirs.
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Sanitize gardening tools regularly with a disinfectant.
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Apply preventative fungicide sprays in early spring if diseases have plagued you before.
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Monitor for and control insect pests like thrips that can damage leaves. Neem oil works great!
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Fertilize peonies in spring to promote strong growth and disease resistance.
Treating Existing Black Spots on Leaves
If those pesky black spots show up despite your best efforts, here are some treatment strategies:
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Improve drainage and cut back on watering if over-wetness seems related.
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Apply neem oil or fungicidal soap sprays to fight fungal and bacterial diseases.
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Remove badly infected leaves or entire plants to prevent disease spread.
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Fertilize peonies with a balanced organic granular fertilizer to provide nutrients.
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Try a dormant horticultural oil spray before spring growth starts to smother overwintering pests/disease.
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As a last resort if a plant is too far gone, destroy it and replace with a new, disease-free peony.
While frustrating, leaf spots are not a death sentence for peonies. With vigilance and prompt care, they can rebound beautifully the following spring. But viral diseases indicate the plant is a goner and should be removed entirely.
When buying new peonies, inspect leaves closely and only select plants with clean, healthy foliage to start with. Follow these tips religiously, and you’ll be rewarded with the peony display of your dreams. Those black spots don’t stand a chance!
Frequently Asked Questions About Black Spots on Peony Leaves
What does peony leaf blotch look like?
Peony leaf blotch causes reddish-purple spots up to an inch wide on leaves, sometimes ringed in yellow. Leaves often curl near infected areas. As it progresses, blotches turn black in the centers.
Can you wipe off black spots on peonies?
No, fungal and bacterial leaf spots can’t be wiped off intact leaves. Gently washing leaves may help slow disease spread though.
Should you remove peony leaves with black spots?
Yes, pruning off infected leaves prevents diseases from spreading. Discard diseased leaves (don’t compost them).
Can peonies recover from black spot diseases?
With prompt treatment, peonies can absolutely recover from fungal/bacterial black spot issues. But viral diseases mean infected plants are goners.
How do you treat bacterial leaf spot on peonies?
Bacterial leaf spot can be treated with copper-based bactericides or streptomycin sprays. But prevention with good care is more effective.
Do peonies get powdery mildew?
Yes, peonies can get powdery mildew. It coats leaves in white powdery patches and may lead to leaf yellowing. Reduce humidity and increase sunlight to treat it.
I hope these tips help you keep your precious peonies looking their absolute best. Don’t hesitate to reach out if you have any other questions. Happy growing!
Diagnosing Peony Leaves with Spots
Here are the most common causes of spotted peony leaves:
Leaf Blotch – Also known as peony measles or peony red spot, this is a fungal disease caused by the pathogen Cladosporium paeoniae. Symptoms are red to purple colored blotches an inch (2.5 cm.) or larger on leaves, and the foliage may be curled or twisted near the spots. Red streaks may form on stems. This disease is most prevalent in mid to late summer.
Gray Mold – A fungal disease caused by Botrytis paeoniae, symptoms include brown to black spots on foliage and flower petals. As the disease progresses, flower buds may turn gray and fall off, and fluffy gray spores will appear on foliage and flowers. Gray mold disease is common in cool, wet weather.
Why Do My Peony Leaves Have Spots?
Spotted peony leaves is usually an indicator of fungal disease. Once a fungal disease is present, there is very little that can be done to treat it. However, preventative measures can be taken to ensure that plants do not get fungal diseases. Preventative use of fungicides in early spring is one method. When using any product, it is important to follow all labeling instructions thoroughly.
Proper cleaning of garden tools and plant debris are also important steps in preventing disease infections. Pruners, shears, trowels, etc. should be cleaned with a solution of water and bleach, between each use to prevent the spread of disease from one plant to another. Fungal disease spores can lay dormant in plant debris, such as fallen leaves and stems. Cleaning up and destroying this garden debris can help prevent the spread of disease.
Fungal spores can also remain in the soil around infected plants. Overhead watering and rain can splash these spores back up onto plant tissues. Watering plants with a slow, light trickle directly at the root zone can help prevent disease spread.