Azalea leaf discoloration
This looks like lacebug damage, a sucking insect on the foliage. This is more common on azaleas in sunny locations.
Damage usually begins on old leaves and later appears on new growth. Turn leaves over to determine how many lacebugs are present. Most species have 2-3 generations a year. When lacebug populations are high, sprays of horticultural oil (at a summer rate), or insecticidal soap will control lace bugs if the lower surfaces of the leaves are thoroughly covered. Do not spray the above products in hot weather and follow all label directions. Monitor throughout the season.
If your azaleas are located in a sunny area, you may want to transplant to a shady location. They grow best in morning sun and afternoon shade.
Thank you! That does sound like what the problem is! They seem pretty well infested so maybe I need to use something stronger than hordiculture oil? I will go to my local gardening store and ask what they recommend as far as chemicals. Unless, you know a kind of chemical that could work in such bad infestations? Also, the azaleas are currently in an area that gets shade in the morning and sun in the afternoon...is this ok for them? It looks like they have been in this location for years. I just bought this house.morning
In this location you will be battling lacebugs in the future as well. A systemic insecticide may provide temporary relief but if the plants are stressed in a hot, dry location, the lacebugs will be back. They like this environment. Also, it looks like the leaves are small.
If you have a location in afternoon shade, you have the option of transplanting them in early fall. Water before you transplant. Get a good sized rootball, and move to the new location. Keep the shrubs well watered up until the ground freezes. Make sure mulch is no thicker than several inches and away from the base of the stems.
If you decide to transplant, spray now with a summer rate of horticultural oil and spray the leaf undersides. Follow label directions.
Replace the shrubs with plants that will grow best in the site taking into account mature height and width. Possibilities include different holly species.
Thank you for your response. I am sorry to have to move them but understand why and want to make sure they are healthy as they can be and not infested every year. Currently they are next to some Japanese holly which grow very well there! Do you have other plant recommendations that could work in such a spot?
As mentioned above, a mix of different holly species could work well. You have to consider the mature height and width for the location. Visit some local nurseries for more suggestions.