Plants need sufficient water in order to thrive. While the amount of water you give a plant is important--each plant's water needs is different--it is also important to reduce water loss. If not, some of the water you are giving your plant is wasted, and therefore your plant may begin to show signs of water loss, which is usually wilted leaves. Fortunately there are several measures you can take in order to maximize the water you are giving your plant.
Apply about three to four inches of mulch around the base of your plants, including under the canopy and outside of the canopy--about one and a half to three times as wide. Typically, mulch is added just below the widest point of the plant's canopy--called the drip line. However, according to the American Forestry Association and many other horticultural and arborist organizations, you should mulch one and a half to three times as wide as the drip line since the feeder roots can spread that far.
Water the plants near the ground, not from above. Be sure to cover the entire feeder root area which is about one and half to three times the size of the plant's drip line. This will help retain water by reducing evaporation.
Water in the early morning or evening hours, especially on hot, sunny days. Water will not evaporate as fast during the cooler times of the day. If you are watering in the evening, do not wet the foliage since that may cause mildew or fungus to grow (and waste water).
Water your plants slowly. In general, you should only water your plants as fast as the soil can absorb it. If you water more, some water will puddle on top and evaporate.