It was a baby Goldenrod . I hadn t planted this one. This one must be a weed . I froze while I stared at the dainty yellow flower, contemplating its origin and its future in my garden. Most deer resistant gardeners are familiar with powdery mildew, as several of the plants that are staples of our gardens are susceptible to it.
Powdery mildew looks like a white powder on the leaves and buds of plants.
The plant will look like it has a milky white haze around it. In severe cases the plant may drop its leaves early. In late fall, dark specs may appear on the plant. These are over-wintering structures that protect the fungus that causes the disease from frigid winter temperatures. A fungus causes powdery mildew.