Percolation of water through soil draws air into the vacated interstices. Excessive watering or inadequate drainage will prevent this form of soil aeration. Light soils, being less retentive, will need watering more frequently than heavy soils. The former need to be watered moderately heavily every four or five days. A soaking once a week will be best for the latter. Excessive watering will wash away small quantities of plant foods; frequent light watering will draw roots to the surface and render them more susceptible to the evils of temperature variations.
Overhead watering will fill half-open blooms with water, rendering them top-heavy, and, in bending over, each flower will tend to open in an ugly, uneven manner. It has been proved that leaves that remain wet for over six hours are rendered more susceptible to black spot and mildew. Hence one should do as much as possible of the necessary overhead watering early in the day, preferably before noon. Nevertheless, Nature waters from overhead. All fungus diseases thrive under moist, humid conditions, such as exist in February and March, when almost every morning the whole garden is weighed down with heavy dews, which deposit much more water on the leaves than any sprinkler. When the weather is showery it is of great advantage to supplement Nature's water with hosing; the atmospheric conditions are then ideal. Dew probably contains minute quantities of plant foods that appear to be absorbed through the leaves.
There are several ways of avoiding wetting the foliage in the course of watering. Some people, using a cultivator or hoe, make small irrigation channels amongst their rose plants and run water along them; others tie a sack over the nose of the hose, lay it on the bed, turn the tap on fully and move the hose from time to time; while a few screw a porous plastic hose on to their garden hose and lay it in between the roses. This is called a soaking hose. You a find all information about roses care, planting and watering with "plant identification app photo" - https://apps.apple.com/us/app/plantspot-plant-identification/id1437376141 on itunes for free.