Flame Azalea (Rhododendron calendulaceum)

2015-5-16 Mt. Cuba Center, New Castle County, Hockessin, DE
Flowers in Spring at low elevations:
http://alabamaplants.com/Others/Rhododendron_calendulaceum_page.html
http://www.nps.gov/grsm/learn/nature/common_spring_wildflowers.htm
"The flowers are very showy and range in color from yellow to deep orange.":
http://www.carolinanature.com/trees/rhca4.html

Plum-leaved Azalea (Rhododendron prunifolium) is similar but blooms in Summer and has dark, green, shiny leaves according to:
http://www.mtcubacenter.org/plant-finder/details/rhododendron-prunifolium/
This Azalea is blooming here in Spring, and this picture was taken five weeks before Summer.

for R. prunifolium see also:
http://www.discoverlife.org/mp/20q?search=Rhododendron+prunifolium
http://www.finegardening.com/plumleaf-azalea-rhododendron-prunifolium