Hi! Try putting some banana peels at the base of your rose. Bury under a little dirt or mulch so it stays moist enough to decompose quickly. The potassium is what causes blooms to be able to form.
When I answered your question yesterday I assumed your roses are in an outdoor garden in the ground. Excuse me if they are potted plants. If they are in pots, regular fertilizer would probably be best.
Does the plant look healthy otherwise ? Does it get full sun ? Roses that are in shade will not produce flowers or may just make one or two.
