Beginner Gardening: Nandina losing leaves, 1 by Debira_Garden

Debira_Garden wrote:
About a month ago, one of three of my Nandena bushes began to lose its leaves from the ground to two-thirds up the bush. Then, about two weeks ago, the two on each side began to do the same thing. I ask a sales person at a Garden Center what they thought it could be. Their answer was grubs, and I purchased some granules to sprinkle around the base of each plant and watered as instructed. The problem has not stopped, but seems to be worse. What else, besides grubs could be causing all of the bottom leaves to fall off?