Warmer weather brings on new growth and the temperature conditions to start the growth of Black spot spores, which leads to rose leaf defoliation. Consider spraying a contact and systemic fungicide now to prevent a hard to control black spot outbreak in March. For example: Bonide’s Revitalize (if you are into organics) or Bonide’s Infuse combine with Bonide’s Mancozeb Flowable w/Zinc.
