If you know exactly when to fertilize roses and get the job done at the right time, you will certainly reap the rewards: a show of bigger, better blooms, and healthier plants in the long run.
As a very general rule, roses should be fed in spring and late summer, but zone-by-zone and rose type by rose type, there will be subtler variations. 'Roses generally are quite hungry plants and appreciate feeding annually with a top-dressing of balanced slow-release fertilizer applied in spring and again in mid-late summer,' says H&G's gardening expert John Negus.
