That all depends on the type of rose seed it is. Some can take up to three years to germinate.
I started some rogusa rose seeds this spring. Planted them in individual cells in a tray. Used bottom heat and grow lights. after 2 months there was still nothing so I started checking on the net as these roses were for a community project and we needed 100 rose bushes by early summer.
Thats were I found out that they could take 3 years. Needless to say I did not have 3 years to wait. I than took all the seeds out of the cell (150 of them) and planted them all in one tray and placed it in the freezer for 2 weeks, then under grow lights for 2 weeks, then freezer, then grow lights, then freezer then grow lights. I ended up with around 65 rose seedling in the end. I used the dirt they were planted in when I transplanted them so if the rest decide to grow they can.
To make a long story longer its best to check the net for the kind you are trying to grow and see what they have to say but you can trick mother nature.