Experts and BHG readers answer.
small black dots on leaves of Mock Orange shrub
The symptoms you describe don't sound like any of the typical disease or insect pests that bother mock orange (Philadelphus species). Mock orange can be sensitive to excessive fertilizer, so if yours is in a lawn area that you fertilize regularly, that could explain the failure to bloom and brown leaf edges, but not tiny brown spots or dessicated spots in the center of leaves. Snip a branch and take it into a local garden center with a Certified Nursery Professional on staff for diagnosis. Your local experts often see the same problems cropping up in the community again and again, sometimes triggered by local conditions.