Plant types, soil types, sun/shade exposure, and the climate you are in will dictate your watering schedule for the plants in your yard. Water deep and thorough, and as needed to prevent your plants from being stressed. Plants that are not stressed remain vigorous and can ward off problems easier and recover faster if there is a problem.
Water the soil at the roots always, don’t spray the leaves of any of your plants whether they are trees, shrubs, roses, annuals or perennials.
Don’t use a nozzle on your hose, just use the hose itself to water your plants. Spray nozzles will tempt you to spray the flowers and leaves of your plants and that is exactly what you DO NOT want to do.
Morning watering is best if you can, that way if you do get more than the soil wet, they begin to dry very quickly. They key is to keep your plant tops dry.
Lastly, how do you know if your plants need water? The best method is to touch the soil at the roots and if it feels moist - skip watering that day. If the soil feels dry, give your plant roots a good drink.