Just as roses can be high maintenance with their required pruning and care, so can managing common black spot disease which so often infects the flowering plant. Several options are available to homeowners to prevent the disease from destroying a rose bush. With a little persistence, this high-maintenance disease can be controlled.
Use a fungicidal spray such as Daconil or Funginex, readily found in nurseries and garden centers. Begin managing the disease during the plant’s dormant season, in the winter. Spray weekly, until the weather becomes hot and dry. Spray only after each rain in cooler weather. Apply the spray in the early morning or evening.
Promote good air movement within the garden. Prune neighboring vegetation for better air flow to speed up plant drying time, therefore reducing the time the fungus has to invade a plant. Avoid overhead watering of rose buses, too.
Plant roses that are highly disease resistant. Consider the David Thompson, a red shrub, Jens Munk, a pink shrub, the Knock-Out rose and Easy Elegant Rose. Control black spot disease by other natural methods, such as adding baking soda to a container of horticultural oil. Spray the solution onto rose bushes to reduce the occurrence of black spot disease. Fertilize rose bushes with one cup of Epsom salt each month to produce more vigorous and healthy plants.