Answer: Roses need a lot of sun in order to set flower buds. Is yours growing tall so it can reach what light is available? Also, roses need lots of nutrients to perform well. Mulch with organic materials such as compost, wood shavings and aged manure. Mulch also provides the perfect medium over which you can apply concentrated fertilizers.
Always apply granular fertilizers, in accordance with the manufacturers suggestions, around the dripline of rosebushes. A dripline is the imaginary circle that would exist if bushes were dripping from being soaking wet. Roses love epsom salts (magnesium sulfate) in the spring. It activates plant enzymes essential to the growth process. You can buy it at the local grocery or drugstore. Apply 3/4 cup epsom salts per plant and water it in well. When summer arrives switch to granular, water soluble, balanced fertilizers such as 10-10-10. Again, water them in well.
Do not fertilize in the autumn. This will stimulate growth that will be tender and vulnerable to frost.
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