RHODODENDRON AND AZALEA CULTIVAR PERFORMANCE IN THE GREAT PLAINS AS AFFECTED BY LANDSCAPE EXPOSURE
Lepidote and Elepidote Rhododendron cultivars were established May 2, 1988 in selected landscape sites with amended soil to evaluate performance under stress by the continental climate characterized by hot summers and cold, desicatting winters. Evergreen azaleas were also screened with emphasis on flower bud hardiness. Survival and flowering were acceptable in exposures protected from winter sun especially on Lepidote `PJM Victor' which survived 42°C although Phytophthora root rot occurred in hottest locations. In contrast flower buds on large leaf types `Nova Zembla' and `Roseum Elegans' often failed to open due to desiccating winter conditions. Cultivars which flowered best after 3 years were `Aglo', `Lodestar', `Nova Zembla', `Olga Mezitt', `PJM', `Waltham' and `Windbeam'. Hardiest azaleas which flowered following -28°c were `Boudoir', `Caroline Gable', Kaempferi `Herbert', poukhanense `Karens', `Pride's Pink' and `Snowball'. Additional cultivars appear promising given suitable bed preparation, proper exposure and adequate maintenance in spite of climatic extremes in the great plains.