Add 1 tsp. of liquid food coloring to 1 cup of water. Drizzle the colored water onto the soil surrounding the base of a plant. Wait 24 hours for the water to absorb. Apply another identical dose if the color change was not sufficient.
The rainbow rose is a rose which has had its petals artificially coloured. The colouring method exploits the rose’s natural processes by which water is drawn up the stem. By splitting the stem and dipping each part in a differently coloured water, the colours are drawn into the petals resulting in a multicoloured rose. Besides roses, other cut flowers can also be coloured using the same method.
According to author and horticultural professor Jeff Gillman, who has conducted extensive research on blackspot remedies, a spray composed of one part milk and two parts water is the best answer to the disease. He says this simple solution, if applied weekly, will control blackspot as well as any synthetic fungicide, including Chlorotalonil.