Caring for rose bushes is important to their overall health and vigor, especially when it comes to watering. Roses require at least an inch (2.5 cm.) of water weekly throughout their growing season, beginning in spring or following spring planting. While overhead watering is suitable before the onset of new growth, it is often better to water these plants at the soil line using soaker hoses or similar means. Rose bushes are very susceptible to fungal diseases, such as black spot and powdery mildew, especially when their foliage is kept too wet.