Roses stressed by the hard freezes this winter are especially hungry right now. High nitrogen is the key to encouraging roses to recover. Look on your fertilizer label, try to find a 50% Nitrate form, which is a fast acting nitrogen, combined with other slow release, such as Urea or Ammoniacal nitrogen. You can start with a water soluble fertilizer, which is a quick feed, but must be repeated at least monthly. A controlled release fertilizer with the Nitrate nitrogen is best. Organically based fertilizers should be combined with a controlled release fertilizer, however, organic fertilizers usually last no more than 6 weeks.