Roses, crape myrtles, Impatiens, and walnut trees are the hosts to some pesky pests.
Rose Rosette Disease is not new but we are continuing to see much impact. The summary version is this: a probable virus, spread by a mite, for which there are not currently controls, may affect any variety and species of rose, after which it will decline and die. Signs include excessive thorniness especially internodal thorns, deformed red cluster of foliage and buds, plant die back. This is not spread through poor hygiene or handling, only through the insect vector. More information at this link:
Impatiens downy mildew and Impatiens Necrotics Spot Virus is affecting bedding plants in over 30 states in the U.S. A IPM approach (Integrated Pest Management) calls for rotating crops in planting beds, and nursery-level control.
Plants which appear not to be affected are New Guinea Impatiens, SunPatiens, as well as other species for shade like annual and hardy Begonia. And shade perennials.
Crape Myrtle Bark Scale is appearing in west Tennessee. Scale is an insect. Its feeding patterns may stress crape myrtles and reduce flowering. Of course there are other reasons for shrubs to be non-performing and if you have a concern, look at the big picture including siting, soil/shade needs, soil testing and nutrition, the possibility of environmental or mechanical stresses.
Here is an article from the University of Arkansas.
Walnut trees and Thousand Cankers Disease