Fertilize rose bushes every four to six weeks during their specific growing season, or once there is about 6 inches of new growth visible. Fertilization should continue through the spring and stop about eight weeks before frost typically begins. A fertilizer that contains a proper balance of the necessary nutrients for roses is ideal, though more generic fertilizer can work as well.
Roses require a constant stream of nutrients to thrive, especially the varieties that bloom repeatedly season after season. Regular and careful fertilizing is required in order to ensure that rose bushes are properly equipped to survive in a garden. Before buying any fertilizer, it is important to test the garden soil and understand what natural nutrients are present. A soil test kit reveals information such as pH balance. The ideal pH range for rose bushes is between 5.5 and 7.0.
Once the soil has been analyzed and any additions to the soil have been made, it is time to purchase a fertilizer. Roses need certain elements, such as nitrogen, copper, phosphorous, calcium and zinc, to grow strong and healthy. Both organic fertilizer, such as manure or animal products, and inorganic fertilizer, which consists of synthetic materials, can be used on rose bushes.