Watering Roses in Shady Areas

We received this question regarding watering roses in more shady areas from a client recently:

Q: We have several varieties of Rose Bushes in our garden. The sun is indirect there and there are trees doing their best to take over. We have been watering these roses every day … in what seems like hours the water has been running.

What would be your recommendation. The soil is rather sandy and tight, but moist.
A: Here is some advice from Berkeley Horticultural Nursery on ‘Growing Roses in the Bay Area:’ “Watering – in the ground: Water established plants deeply at least once a week) more often in hot or windy weather, less often during cool foggy spells). Soaker hoses snaked between the plants will make watering less of a chore and they can be hidden with mulch. Adding 2 in. or more of mulch around roses will reduce the need for water by preventing evaporation.”

Or, Sunset Garden Book recommends basin flooding if you don’t have drip irrigation and are watering by hand — in other words, creating a thick walled basin via a soil berm around the rose bush, about 3 – 4 ft. in diameter, then adding water by the hose to fill the basin. The idea is to deep water with enough water to wet the entire root zone of the rose. In hot weather, you might be filling the basin every other day. In general, by any method of watering, the object is not to get water on the leaves of the rose because it can contribute to mildew.