Rose bushes add beauty and a fragrant scent to your garden. But if a fungus like black spot takes over your rose bushes, it will eat away at the leaves and may eventually destroy your rose bush. Although you can buy a variety of commercial fungicides, these products are costly and are often harmful to the soil and surrounding plants. Make a homemade fungicide with natural ingredients to protect your rose bushes without a hefty cost.
Fill a clean, empty garden sprayer with 1 quart water. Add 1 tsp. baking soda.
Swirl around the sprayer several times so the baking soda completely dissolves. Add 1 tsp. bleach-free dishwashing soap, then swirl the container around again. The soap helps to keep the baking soda on the leaves.
Spray both sides of the leaves on the rose bush so they are soaked with the mixture. Reapply the mixture after rainfall and watering.