Rhododendron ( Tartar Glenn Dale Azalea )
The Glenn Dale evergreen plant loanblend were developed in Maryland from R. indicum , R. kaempferi , R. simsii and many other species and hybrid . They are compact , fan out , evergreen azaleas grow primarily for cold hardiness along the mid - Atlantic state . Flowers are abide in showy corbel of 1 to 4 per cluster . Bloom time is tardy April in warm areas and as latterly as mid - June in cool climate ....