Roses can be very vulnerable once autumn arrives, so generally need a little more care to keep them happy and stay healthy as the weather gets colder. September is when the weather is really rainy but still quite warm which makes it the perfect climate for fungal diseases like black spot as they thrive in hot humid weather.
Black spot gets in name as it will first appear as dark circular lesions on rose leaves, but not only affects the plant’s appearance as it can greatly impact its long-term survival. This disease will greatly weaken roses and cause it to lose all its leaves so it becomes malnourished, which will stunt its growth and leads to it not being able to flower properly.
It is unlikely that black spot can kill roses outright, but it will sap the plant of energy and make it very vulnerable once winner arrives so it is unlikely to survive in the cold.
Fungal spores spread very easily which means it will easily keep coming back to infect roses once it makes its way into a garden.
However, Tony O’Neill, a gardener and founder of Simplify Gardening has explained that preventing black spot is very easy, as all you need is a little baking soda.
He said: “Baking soda creates an alkaline chemical condition on the leaves, making it hard for the black spot spores to sprout. It is because the fungus thrives in more acidic PH conditions. This solution is more effective when you apply it as soon as you see the first signs of the disease.”
Baking soda is simple but very effective at preventing black spot since it rises the pH level on rose leaves, which makes it very difficult for the spores to grow or reproduce.
How to prevent black spot disease on roses
All you need to do is mix two tablespoons of baking soda and a gallon of warm water in a garden sprayer.
It can also be useful to also add two tablespoons of a liquid soap like Castile to your solution, as it will help the baking soda stick to the plant leaves.
Then, simply apply the solution to your rose leaves once a week. Make sure to take the time to apply it after it has rained, as the water will wash off the baking soda.
Baking soda is unlikely to cure black spot, but is one of the best ways to prevent this disease taking root in your garden. However, you also need to make sure your rose bushes are clean and well ventilated.
Black spot thieves with moisture, so make sure you are picking up leaves near your roses and pruning them when needed. Baking soda will only help keep disease away as long as you also have a tidy and well-maintained garden.
