Hello Gary,

This appears to be advanced damage from powdery mildew, a common disease among dogwoods. Some varieties are resistant to this disease, but none are immune, and weather conditions play a large role in disease severity from year to year. Leaves sometimes do not show clearly the typical powdery gray-white coating on the leaves associated with the fungus, and instead show this reddening and scorched portions of leaf. There is little you can do at this point to intervene, though we recommend raking-up and disposing of (do not compost) its fallen leaves this autumn. Next year, since the disease has been pervasive enough to probably interfere with flowering, preventative fungicide treatments may be useful. (They do not cure existing disease, though, so treatment now is not practical, since there is essentially no "clean" foliage to protect.)

More information about mildew (in general) and dogwood diseases (including mildew) can be found on these pages:

powdery mildew - https://extension.umd.edu/resource/powdery-mildew-disease-trees-and-shrubs

dogwood diseases - https://extension.umd.edu/resource/description-and-management-dogwood-diseases

dogwood general care  and resistant varieties - https://extension.umd.edu/resource/how-grow-dogwood

Lack of flowering could also be attributed to (or exacerbated by) insufficient moisture in late summer and autumn. Spring-blooming trees start forming their flower buds the summer/autumn prior to bloom, so if they lack enough water during this growth phase, the buds will either not develop or abort without finishing development. They could also be killed while overwintering if the season is too dry. In recent autumns, we have experienced prolonged dry spells which can stress plants. This year, monitor the root zone for moisture at about a 5" depth and irrigate the area well if it feels fairly dry. (Wet soil at that depth should be fine, so you can avoid over-watering.) While established plants generally need less watering attention than more recent transplants, sensitive species still benefit from the intervention when weather is too stressful for them.

Dogwoods also naturally occur in woodland habitats where they receive some afternoon shade and a more moisture-retentive (and well-draining) soil, mulched in fallen leaves. In our landscapes, conditions are often sunnier and warmer, with more compacted soils and, depending on the gardener, too much or too little root insulation from mulch. If you do have mulch under the tree, keep its depth under 3" and don't let it touch the trunk base. If you don't have mulch and instead have the lawn growing close to the trunk, this added root competition could be contributing to tree stress.

Miri