Hydrangea flowering: Factors include maturity, night temperature and photoperiod; but which have the most effect?

摘要

Growers can't induce flowering of field hydrangeas by just controlling the photoperiod, says a University of Guelph researcher. Contrary to European research, Prof. Theo Blom, Department of Plant Agriculture, showed that photoperiod has very little effect on the flower initiation of the hydrangea, a popular potted plant grown around the shores of Lake Ontario and Lake Erie. Potted hydrangea, Hydrangea macrophylla subsp. Macrophylla, generates 5 million dollar in sales annually for Ontario producers.