Black spot is a fungal disease that can be a problem especially when it gets warm. The spores of this fungus need a few hours immersed in water in order to germinate, so doing everything possible to reduce moisture on leaves and improve air circulation in critical.

-Remove damaged leaves as they appear and pick up any that have fallen, as black spot can over-winter in the fallen leaves.

-Mulching can act as a barrier from the soil and helps to restrict the spread of the spores.

- Lime sulphur is a great preventative on leafless roses over winter. A deficiency in potassium makes them more susceptible.

-Water roses at the base of the plant to try and keep the leaves dry and prevent the spread of the spores.

-Mix 2 teaspoons of bi-carb soda in 5 litres of water and a few drops of of detergent. This makes an inexpensive organic fungicide or use a copper based bought fungicide.