Subject: Maple trees ,

Dear Sharon ,

Thank you for contacting the UNH Extension Infoline regarding your Maple trees in your yard .

Following up on your email from 8-06-2026, I have put together some information below to help get you started.

We are committed to finding the right solutions for your lawn and garden. Please feel free to reach out if you have any additional questions.

Best regards,

Haim
Master Gardener Volunteer
UNH Extension Infoline Volunteer / Staff
University of New Hampshire Cooperative Extension
<personal data hidden> | 1-877-EXT-GROW (<personal data hidden>)

General information

Seeing a mature tree suddenly drop brown leaves in August can be alarming, but this is a very common late-summer response to environmental stressors or seasonal fungal issues.

There are three primary reasons this occurs in New Hampshire maples during August:

Maple Anthracnose (Fungal Infection): If the leaves have dark brown, irregular blotches or shriveled edges that follow the leaf veins, they likely have anthracnose. This fungus thrives during wet spring conditions and causes infected leaves to drop prematurely in late summer. Fortunately, anthracnose rarely kills established trees.

https://extension.uconn.edu/publication/why-are-maple-leaves-turning-brown-and-falling-early/

Environmental Leaf Scorch: If the browning is a clean, uniform band right around the outer edges of the leaves, the tree is suffering from atmospheric or moisture stress. Extended high heat, strong summer winds, or compacted soil can cause the tree to lose water faster than its roots can absorb it. The tree drops leaves to reduce its surface area and conserve moisture.

Root or Soil Issues: Overwatering from a saturated summer or underwatering during a hot spell can cause root stress, mimicking the exact symptoms of drought.

Recommended Action Steps

Sanitation: Rake up and destroy or bag all fallen leaves. Do not compost them, as the fungal spores can survive the winter and reinfect the tree next spring.

Water Management: If the soil under the tree is bone-dry several inches down, provide a slow, deep watering at the drip line once a week. Avoid shallow, daily sprinkling.

Hold Off on Fertilizer: Do not apply fertilizer late in the summer, as this encourages weak, tender new growth right before the winter freeze.

Most healthy maples will recover completely and leaf out beautifully next spring. To provide a more precise diagnosis, it would be incredibly helpful if you could reply with a few close-up photos of the damaged leaves and a clear photo of the entire tree.