The Glenn Dale evergreen hybrids were developed in (Glenn Dale) Maryland from Rhododendron 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 long-lasting and usually in showy trusses of 1 to 4 per cluster. Bloom time is late April to early May 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 azaleas are taller (3-8 feet). Do not be alarmed if plant drops some leaves during colder weather. Filtered light is best. Plant as you would any of the other azalea: high and in well-drained, acid soil, rich with organic matter. The Glenn Dale azaleas are hardy in USDA hardiness zones 6 through 9. The hybrid 'Youth' and the other Glenn Dale azaleas can be found on the Glenn Dale Azalea Hillside in the Azalea Collection. Be sure to check the Azalea Blossom Watch page for the current projected peak bloom dates of all of our azaleas. You can also visit our Glenn Dale Azaleas Photo Gallery were you will find over 200 images of the flowers of more than 100 of the Glenn Dale azalea varieties.