Rose Disease Control
Q: I found a formula in a gardening magazine for a rose disease control spray that contains baking soda, cooking oil and vinegar. What do you think?
A: The problem with recipes like this is twofold: First, mixtures like this are not supported by research. In other words, when scientifically tested, it does not consistently prevent diseases. Generally speaking, that’s because different parts of the country have different amounts of disease pressure. A homemade mixture that might work occasionally in one part of the country (Pennsylvania) might not ever work in another part of the country (Georgia) where heat and humidity conspire to favor disease on roses.
Secondly, this recipe contains vinegar and baking soda, which any elementary school student can tell you will react and neutralize each other.
In Georgia, the best rose disease preventers are synthetic fungicides, like Daconil or Infuse. These materials, in combination with disease-resistant roses, can give you consistently beautiful flowers.