Observation of a Low Temperature Effect on Roses1

Abstract

Abstract Rosa hybrida L. cvs. Forever Yours and Cara Mia, were subjected to split night temperatures from November 1, 1977 to February 8-18, 1978. During the 22 weeks of treatment, split temperatures seriously delayed production and markedly reduced quality. Split temperatures for roses as a means of energy conservation did not appear to be a viable practice. Following the experiment, however, for a 9 week period, after returning night temperatures to 16.7°C, plants in the lowest temperature treatment produced twice as many flowers as compared to the entire previous record with a significant increase in quality and marked increase in bottom shoots. The effect appeared to be cumulative and suggested an inexpensive means for rejuvenating old rose plants.