Ask-a-Dave's-Gardener: Sick Shrubs, 3 by CA2DC

CA2DC wrote:
These shrubs are planted across the front of our house against the porch. At first I noticed a small clump of dead leaves about 4-5 inches in diameter. Over the course of 1-2 weeks the small clump of dead leaves has expanded to about 2 feet in diameter. (I’m in the DC metro area and we’ve had quite a bit of rain throughout the summer and early fall.)

My worry is that it’s some sort of disease that is going to run through each of the bushes until all of them in front of the house are dead. Any help you can provide would be greatly appreciated! Thank you so much!!