when the weather is right, like Oct/Nov in HK around 20C, it is possible to use the cut flower stem as cutting to grow new plant. But most of the cut flower rose are not suitable for general culture. Cut flower roses are usually need lots of manpower to take care and lots of different anti-bacteria/insect sprays to keep them healthy. Moreover, cut flower rose are usually not as pretty as garden rose, so don't waste your time la.