If your plant is what we, here in the U.S., call a peony it's not actually a rose, and is not fertilized as would be a rose. They are very hardy... some have known to be over 50 years old. In fact, here they are also known as a "graveyard bush", since many are planted in cemeteries due to their hardiness.
Use a fertilizer low in nitrogen(5-10-10) ( the first number is nitrogen, then phosphate and potash) into the soil when the stems are about 2 or 3 inches high. Over-fertilizing, especially with a high nitrogen plant food, results in weak stems and reduced flowering. One of the best is a simple working into the soil of a double handfull of wood ashes in the spring...
Best of luck!