Epsom salts are used as a fertilizer for roses (and also tomatoes) because it contains both magnesium and Sulphur which roses need. The usual application is to use one tablespoon of the salts around the base of each rose plant and water well. You can also dissolve the Epsom salt into a gallon of water and use this to water your roses. The problem is if you use too much you can damage or even kill your rose plants. Another issue is that roses all need nitrogen, boron, phosphorous and a number of other nutrients. Roses are hungry plants. It is much more safe and efficient to use a complete plant food with all the macro and micronutrients around your roses. A slow release plant food like Osmocote is a great choice as it contains all the nutrients a rose will need plus the fertilizer is released slowly throughout the growing season as the rose needs it. Why not do an experiment and try Epsom salts on one rose plant and Osmocote on the other? Then your roses can tell you which plant food gives them the most nutrition. Keep growing, Marianne Binetti