Organic types are processed materials such as dried blood, bone meal and manure. Organics have low levels of nutrients compared to the other two, but are the fertilizer of choice with organic growers. Each type of fertilizer has its advantages and disadvantages and the one you choose to use is really a matter of personal preference. Special blends have been created by the industry to make it easier for consumers to purchase exactly what they need. Flowers require higher amounts of phosphorous, so the bag will have a middle number as high as the first.
Roses have special needs all their own.
Look for fertilizers made especially for roses, as it will contain a unique blend of all three nutrients. The nutrients are contained within a coated pellet and as the water penetrates the coating, the nutrients inside come out and disperse throughout the soil. Using this type of fertilizer allows the plant to be fed constantly causing less work for you. Timed-release brands are resistant to leaching and will not burn lawns or plants. If you grow a lot of container pots, it would be a great advantage using timed-release as you will only have to feed once during the season, however, make sure you purchase one that will last the correct amount of months for your particular growing season.