R. L. Ticknor, Aurora, OR
Photo by R. L. Ticknor
R. 'Shamrock' is a hybrid of R. keiskei (Dwarf form) X R. hanceanum nanum done in 1971 . After 6 years, the original plant was 10" tall and 25" wide, however cuttings grown from the plant appear to be growing faster.
'Shamrock' was selected for its compact habit and chartreuse flowers - R.H.S. colour chart 154D. There are 8-9 flowers 1¼ inches in diameter per truss and most terminals have flower buds. Plants in flower 8-10 inches across can be produced in 18 months from inserting cuttings which root readily over a long period.
The yellow green flowers make a good contrast in the landscape with the blue and purple lepidote rhododendrons which bloom at the same time. The flower color and blooming time around March 17th offer the possibility for use as a pot plant for St. Patrick's Day.
Plants were released to nurserymen in Oregon and Washington for increase in Spring 1978. Since it has not been grown on the East Coast, the hardiness is not known at this time but the parent species can be grown from Long Island south.
The following appeared recently in Ornamentals Northwest, Dr. James Green editor.
At the Oregon State Federation of Garden Clubs' state convention, June 19-22, 1978, at Timberline Lodge, OR, Dr. R. L. Ticknor (North Willamette Experiment Station, OSU) received the Horticulture award in recognition of his 2 new rhododendron cultivars, 'Blaney's Blue' and 'Shamrock', development of 1-gallon containerized rhododendrons for use as a flowering potted plant in the florist trade, and development of improved hollies and table grapes suitable for the Pacific Northwest climate.