This study was conducted to determine the applicability of the shoot growth model to cut roses grown at high temperatures. Two cultivars of cut roses, ‘Antique Curl’ and ‘Beast’, were cultivated in growth chambers set to night/day temperatures of 24/20°C for the control group and 32/28°C for the treatment group. The shoot growth model, which resulted in high coefficients of determination (R2 = 0.80 and 0.62, respectively, for ‘Antique Curl’ and ‘Beast’), was a good predictor of the decrease in the growth of rose shoots for both treatment groups. Although the model produced good results for both the control and treatment groups of ‘Antique Curl’, the accuracy of the model can be improved by using the modified leaf area at the harvest stage. From these results, the model was confirmed to perform well for predicting a decrease in productiveness and quality in cut roses cultivated during summer under high temperatures.