The flowering of 32 New Zealand chestnut(Castaneaspp.) selections and introduced cultivars, growing in the Waikato region of New Zealand, was monitored over three consecutive seasons. Dates of anthesis and stigma emergence and expansion were noted, and a range of early‐late flowering chestnuts identified. For the important New Zealand commercial selections ‘1002’, ‘1005’, ‘1007’, ‘1011’, and ‘1015’, the timing of the optimum pollination period was assessed using a time‐sequence bagging trial and estimated to have occurred from c.l to lOJanuary 1994. This was later than most pollen release and may help explain the low and variable levels of nut production often observed in the field. Nut production generally increased with the length of time for which stigmas were exposed for open pollination. In selection ‘1005’, exposure for 1 week was too short for any successful pollination to occur. A single application of hydrogen cyanamide (Hicane®) at 3% a.i. on 10 August 1993 advanced the time of leaf emergence and the time of flowering in all five New Zealand chestnut selections tested.