Chilling Units Used to Determine Rooting of Stem Cuttings of Junipers
Stem cuttings from 10 juniper cultivars, representing 5 taxa of juniper (Juniperus chinensis L. ‘Pfitzer Aurea’; J. horizontalis Moench ‘Bar Harbor’, ‘Prince of Wales’, ‘Wiltoni’, ‘Youngstown’; J. procumbens Endl. ‘Green Mound’; J. sabina L. ‘Broadmoor’, ‘Buffalo’, ‘Tamariscifolia’ and; J. scopulorium Sarg. ‘Wichita Blue’) were inserted into rooting beds twice monthly from October 15, 1986 to February 28, 1987. During this time period, air temperature was monitored continuously 1 m (39 in) above the stock plants and seasonal chilling units (i.e., hours at ≤55°C (41°F)) were determined. Chilling units of the donor stock plants affected the percent rooting of most juniper cultivars. Data suggest that the optimum rooting period of most cultivars of juniper can be determined by their chilling units.Abstract
Contributor Notes
2Research Forester and Research Scientist, resp.