here are lots of products for fertilizing Roses and Roses need fertilizing for the best blooms. A household product that works well is Epsom Salt. The Magnesium Sulfate in Epsom Salts is great for Roses. All you do is take a half cup of Epsom Salt Crystals and sprinkle it around the Rose, once in the Spring and once in the Fall. That will be enough when you water it in to get those blooms going. The only thing to be concerned about is if you have high magnesium levels in your soil. It is always a good idea to have your soil tested periodically.