"Water regularly" means don't allow the soil to dry out. You want to keep the soil moist, but not wet. About 1 inch of water each week should be enough. That includes any rain that falls. Use a rain gauge to determine how much rain falls during each storm. If it is less than an inch, you will need to water your shrub so that it gets a total of 1 inch of water that week. You can also add a thick layer of mulch, about 2 to 3 inches deep, around your shrub to help keep the soil moist. Don't let the mulch touch any of the stems. It should be covering the soil but not touching your shrub. Mulch should never touch your plants, shrubs, and trees. Those cones of mulch that you see are actually killing the poor trees. When mulch touches a plant, shrub, or tree, it provides cover for destructive insects and small animals to live in. They will chew on and ultimately kill the plant/shrub/tree.