Azaleas in southern delaware
Hold off on the fertilizer until next year to see if they bloom. This year was so very unusual with the weather the flower buds may have frozen and not been able to bloom. If you fertilize now, they will put out more growth which may be damaged if we have an early frost.
Early spring, when you see the buds starting to form, you may want to give your azeleas a light fertilization. After they bloom, you can fertiilize more heavily with an acidic fertilizer.