Hydrangeas, Azaleas, Banana Shrub, Helleborus, Hypericum, Andromeda (Pieris) are some shrubs that come to mind. If a perennial will interest you and you'd like colorful foliage as a substitute for flowers, check out Coral Bells (Heuchera), Hosta. On your next store visit, ask our staff to show you some other suggestions that I'm sure that I've overlooked here.