Thank you for reaching out to us. Your plant is a type of ninebark (Physocarpus opulifolius). There are a variety of cultivars on the market with varying leaf colors ranging from deep burgundy to golden yellow.

https://plants.ces.ncsu.edu/plants/physocarpus-opulifolius/

Unfortunately, many of the cultivars are susceptible to power mildew, a fungal disease, the signs of which we see on your plant. Fungicides are available to control powdery mildew on shrubs, but they are only effective as a preventative measure. They are not curative once symptoms are already present. Since ninebarks have just finished their flowering, you can prune your plant to remove the worst areas and try to thin out the plant to improve air circulation. Since this type of plant is very susceptible to powdery mildew, you might consider treatment early in the season next year, or replace the plant with something else that is less susceptible.

Here is our web page on powdery mildew and management options. https://extension.umd.edu/resource/powdery-mildew-disease-trees-and-shrubs

Christa