Start with the large, established trees. These are the most difficult and expensive to replace if they don’t survive. They also take the longest to become established. While they may not require supplemental water during a short drought period, if it becomes prolonged established trees can still suffer. Next, care for the young trees which are still developing their root systems.
Take care of shrubs next, followed by perennials, lawn and finally, annuals. This order will direct your attention to the plants that have had the most invested in them saving you time and money if you must replace plants that don’t survive. (Cynthia Domenghini)