|The Glenn Dale evergreen hybrids were developed in Maryland from R. indicum, R. kaempferi, R. simsii and many other species and hybrids. They are compact, spreading, evergreen azaleas developed primarily for cold hardiness along the mid-Atlantic states.
Flowers are borne in showy trusses of 1 to 4 per cluster. Bloom time is late April in warmer areas and as late as mid-June in cooler climates. This is usually a back of the border azalea because most of the Glenn Dales are taller, though not all. Do not be alarmed if plant drops some leaves during colder weather. Filtered light is best.
Plant as you would any of the other azaleas: high and in well-drained, acid soil, rich with organic matter. Though azaleas have a potentially large list of possible pest and disease problems, they are usually trouble free if planted correctly in proper cultural conditions.