Hello Mary,

You will get three (3) separate responses based on what I see in your images and your description of each plant.

BOXWOODS

Browning boxwoods in Michigan can stem from several causes, and your image—showing outer foliage discoloration with inner greenery—offers helpful clues. Here's a breakdown of the most likely culprits based on Michigan State University Extension and other university sources:

Look at the information at this link:

What’s wrong with my boxwood? Boxwood pests and other threats - Floriculture & Greenhouse Crop Production

️1. Winter Injury (Most Common Cause)

According to MSU Extension, winter damage is the most frequent reason for browning in Michigan boxwoods, especially after harsh temperature swings or deep freezes below –10°F.

Symptoms: Browning on outer leaves above the snowline; inner foliage remains green.

Triggers: Sudden warm spells followed by cold snaps, exposure to winter sun or wind, especially near pavement or siding.

Management:

Prune out damaged areas in spring.

Mulch to regulate soil temperature and moisture.

Avoid late-season nitrogen fertilization.

MSU Extension: Browning of boxwood – Is it boxwood blight? - Check out this link:

Browning of boxwood: Is it boxwood blight? - Landscaping

2. Boxwood Blight (Calonectria pseudonaviculata)

This severe fungal disease was first confirmed in Michigan in 2018. It’s less common than winter injury but worth ruling out.

Symptoms:

Rapid leaf drop.

Brown leaf spots with dark borders and yellow halos.

Black streaks on stems.

White, frosty fungal spores on leaf undersides in humid conditions.

Check out this link:

Browning of boxwood: Is it boxwood blight? - Landscaping

3. Volutella Blight (Pseudonectria spp.)

Another fungal disease that mimics winter injury, causing branch dieback.

Symptoms:

Leaves turn red, then bronze, and finally yellow.

Loose bark and stem girdling.

Salmon-pink fungal fruiting bodies in moist weather.

Management:

Prune infected branches when dry.

Thin interior stems to improve airflow.

Remove fallen leaves and debris.

University of Maryland Extension: Volutella Blight of Boxwood at this link:

Volutella Blight Disease of Boxwood | University of Maryland Extension

Diagnosis Tips

Uniform browning = likely winter injury.

Spotty or progressive dieback = possible disease.

Best practice: Submit a sample to MSU Plant & Pest Diagnostics for lab confirmation.

I highly recommend sending your images by email to the MSU Plant & Pest Diagnostics Lab to receive a confirmed and precise diagnosis and identification.

Their email is <personal data hidden> - Please include your first and last name.

The experts there can also provide you with the best treatment options.

The lab will notify you if they require a sample to be sent.

The lab may also ask for additional images. So be prepared.

Their website is at this link:

Plant & Pest Diagnostics (msu.edu)

Their Contact Information is at this link:

Contact Us - Plant & Pest Diagnostics (msu.edu)

This link will explain the details on submitting a sample to the MSU Plant & Pest Diagnostics Lab:

Submit Samples - Plant & Pest Diagnostics (msu.edu)

I hope this helps!

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PEONIES

Several factors could cause the milky appearance of your peonies' leaves:

Crown Rot: This condition can deteriorate the plant's health, leading to milky, discolored leaves.

Powdery Mildew: A common issue that can appear as a white powder on leaves, especially in shaded areas with poor air circulation.

Fungal Infections: Fungi like Sclerotinia can cause symptoms such as fluffy white mycelia under humid conditions.

More information at this link:

How to Manage Potential Problems Growing Peonies | Yard and Garden

Based on the symptoms you described and what’s visible in the photo, the milky appearance on peony leaves is most likely caused by powdery mildew, a common fungal disease in Michigan gardens, especially later in the season.

 What Is Powdery Mildew?

Caused by fungi in the Erysiphaceae family.

Appears as white to gray powdery growth on leaves, stems, and buds.

It thrives in humid conditions with poor air circulation, especially in shaded areas.

Doesn’t usually kill peonies, but it can make them look unsightly and reduce vigor.

About Davonil

Davonil is a dinocap-based fungicide, typically used for controlling powdery mildew. It’s effective preventatively but won’t reverse existing damage. Once the mildew is visible, fungicides primarily help limit further spread, rather than curing infected tissue.

Management Tips for Michigan Gardens

Sanitation: Remove and discard infected foliage in fall—don’t compost it.

Airflow: Thin surrounding vegetation and space peonies to improve circulation.

Sunlight: Powdery mildew is more severe in shaded spots; consider relocating or pruning nearby plants.

Resistant Cultivars: If this issue persists, trialing mildew-resistant peony varieties may be beneficial.

Extension Resources

You might find these university-backed guides helpful:

Iowa State Extension on Peony Problems – At this link:

How to Manage Potential Problems Growing Peonies | Yard and Garden

UMN Extension on Powdery Mildew – At this link:

Powdery mildew in the flower garden | UMN Extension

Illinois Extension on Peony Leaf Diseases – At this link:

What are those spots on my peony? Powdery mildew and leaf blotch | Good Growing | Illinois Extension | UIUC

I hope this helps!

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HYDRANGEAS

If your hydrangea is only blooming once, it may be due to several factors:

Old Wood: Most hydrangea varieties bloom on old wood, which means flower buds from the previous year are still present.

Winter Damage: Early or late freezes can damage flower buds, preventing blooming.

Improper Pruning: Incorrect pruning can hinder blooming; ensure you prune at the right time for your specific hydrangea variety.

Nutrition and Light: A lack of nutrients or insufficient light can also impact blooming.

By addressing these factors, you may encourage your hydrangea to bloom more consistently.

Sources at links below:

Why Doesn't My Hydrangea Bloom?

Hydrangea: Failure to bloom | Hortsense | Washington State University

Thanks for the image and context—your hydrangea looks healthy overall, but that sparse blooming pattern is definitely worth troubleshooting. Based on Michigan’s climate and your expertise, here are the most likely culprits:

Common Reasons for Sparse Hydrangea Bloom in Michigan

1. Wrong Pruning Timing

If your hydrangea is a bigleaf (Hydrangea macrophylla) or oakleaf (H. quercifolia) type, it blooms on old wood—buds formed the previous season.

Pruning in fall, winter, or early spring can accidentally remove those flower buds.

Smooth (H. arborescens) and panicle (H. paniculata) types of bloom on new wood, so they’re more forgiving.

Solution: Identify your hydrangea type and prune only right after flowering if it blooms on old wood.

2. Winter Damage to Buds

Michigan’s late frosts or harsh winters can kill overwintering buds on old-wood bloomers.

Even if the plant leafs out beautifully, flower buds may have been lost to the cold.

Solution: Protect with burlap or mulch mounds in late fall. Consider cultivars like Endless Summer, which bloom on both old and new wood, ensuring a steady supply of blooms.

3. Too Much Shade

Hydrangeas tolerate shade, but too little sun can reduce blooming.

Bigleaf and oakleaf types prefer morning sun and afternoon shade.

Solution: If your plant is in deep shade, consider thinning nearby vegetation or relocating to a spot with dappled light.

4. Nutrient Imbalance

Excess nitrogen promotes lush foliage at the expense of flowers.

Phosphorus is key to blooming.

Solution: Use a balanced fertilizer, such as 10-30-10, in early spring. Avoid high-nitrogen lawn runoff near the root zone to prevent damage.

5. Florist/Gift Hydrangea

If this were a potted gift plant, it may be a non-hardy cultivar not suited for Michigan winters.

Solution: Try replacing it with a hardy, reblooming cultivar bred for northern climates.

Want to Dig Deeper?

You could:

Check for bud formation in late summer to assess winter survival.

Try a soil test to evaluate pH and nutrient levels—especially phosphorus and aluminum if you’re aiming for blue blooms.

Information on soil testing at this link:

Soil testing through MSU Extension - Soil Health