The growth of flower buds of 'Sarah Bernhardt' were accelerated by pre-chilling for 10 days, and some differences were recognized between flower bud of pre-chilling plot and that of control at the end of pre-chilling and chilling. Sprouting, budding and flowering were also accelerated by the pre-chilling. The pre-chilling had virtually no effect on cut-flower quality at anthesis, except that the petal number and flower weight of plants were decreased, by the treatment.
In wild type of herbaceous peony (Paeonia lactiflora), the flowering date of plants pre-chilled for 10 days and chilled for 30 days was almost the same as that of plants chilled for 40 days, though the flowering per-centage of the former was much superior to that of the latter. The cut-flower quality was good in both plots.