Can I cut back diseased leaves on my rose bushes now?
It is probable that your roses have black spot. Remove all affected leaves from the shrub now, it will not hurt the shrub at all even is there are no leaves left. Clean up any leaves on the ground and bin or burn them all, do not put them on your compost heap. Black spot spores live in the soil over winter. Next spring start to spray the soil and roses with a fungicide before any new growth appears and continue with a spraying regime throughout the season.