What is a simple solution for black spot on roses?

Question

My climbing rose bush recently developed some black spot. I would prefer to use an organic method but am open to suggestions. Thanks!

Answer 1

Two thoughts: one is horticultural oil spray used to smother insects also puts an oil barrier on the leaves resisting black spot spore germination. The oil must be on before the spores.

Here is a website to show you other possibilities. Remember the best "cure" is prevention.

Bicarbonate of Soda Sprays
World-wide gardeners are turning to Organic Gardening to improve their own health and to eliminate harmful pesticides and chemicals from their immediate environment.
There are a multitude of organic gardening remedies that can easily be made at home to control common garden fungal diseases, such as powdery mildew and black spot.

Home-made Fungal Disease Preparations for Black Spot and Powdery Mildew
Using Bicarbonate of Soda ( Baking Soda, Sodium bicarbonate ), a spray can be made that will effectively control powdery mildew and black spot.

Powdery Mildew : To one bucket of water add 7 teaspoons (20 grams) of bicarbonate of soda and sufficient laundry soap to make a rich lather. Stir the mixture to dissolve the bicarbonate of soda powder. Spray both sides of the affected leaves.

Black Spot : To 10 litres (USA=21pints, UK=17½ pints) of water add 1 tablespoon (USA/UK=3 teaspoons) of bicarbonate of soda, 1 tablespoon of soap detergent and 2 tablespoons of white oil. Stir the liquid to completely dissolve the bicarbonate powder.
Before applying the mixture first water the rose's foliage to remove any dust and allow the leaves to dry. NEVER spray in full sunshine or in the heat of the day as the leaves may burn, instead wait until early evening.

White Oil : Proprietary brands of White Oil are available but it is very simple to make; blend together 1 cup (USA/UK=1¼cups) of cooking oil, 1½ cups (USA/UK=2cups) of water, and 1 teaspoon of dishwashing liquid. Dilute this mixture at a rate of 3 teaspoons per ½ litre (USA=1pint, UK=16 fl.ozs) of water for spraying.

White Oil Precaution
It is possible for White Oil to stunt the growth of ferns and orchids. To prevent this occurring, dilute the spray to 3/4 strength and do not spray when the temperature is above 25°C (77°F).

Answer 2

there is nothing like chemicals - go and buy the spray can for rose rusts!