Rhododendron hybrida ( Cantabile Glenn Dale Azalea )
vertical to widely spreading , evergreen plant azalea evolve primarily for cold hardiness along the mid - Atlantic states . Single , funnel shape - shaped , white flowers , 2 to 2 1/2 inches broad . bloom are wear in showy trusses of 1 to 4 per bunch . Bloom time is late April in warmer areas and as late as early June in nerveless climates . Plant as you would any of the other azaleas : high and in well - drain , acid soil , deep with constitutive matter ....