Rhododendrons in Vermont
From "The Green Mountain Grower",
Extension Service University of Vermont
Dr. N.E. Pellett, Editor
Six of the most cold hardy cultivars of broadleaved rhododendrons were planted in spring of 1974 at four test sites in Vermont. Donated by the Vermont Plantsmen's Association, these cultivars are growing at Benningtbn College, Oxbow Union High School in Bradford, Lake Region Union High School at Orleans and the UVM Horticultural Research Center in South Burlington. The rhododendrons are located in an open exposed area at each site. Two or more plants of each cultivar were planted on the north and south side of a snow fence to compare exposure effects. Plants are mulched with black plastic to control weeds and are fertilized each spring with a 10-10-10 fertilizer.
The cultivars 'Caractacus', 'America', 'Roseum Elegans', 'Nova Zembla', 'Boule De Neige' and 'PJM' are growing at the four test sites. At Bennington, the mildest site, all cultivars have grown and flowered well. At the colder sites in So. Burlington, Orleans, and Bradford, the cultivars, 'PJM', 'Boule De Neige' and 'Roseum Elegans' had the least winter injury. Cultivars, 'America', 'Caractacus' and 'Nova Zembla' had brown leaves and injured flower buds in the spring at the colder sites.