It's best to deep water so the moisture reaches the thirsty roots. About once every 7-10 days I have a slow drip on the established plants I am concentrating on saving. Depending on the size of the tree/shrub or type (Canna, daylily, etc) the drip is from 1/2 hr to several hours.
Also, I keep an eye on my neighbor's watering habits. Some of my perimeter plants don't need my water at all. My neighbor's watering will sustain them. Their roots grow to seek the wetness on the other side of the fence. I do need to make sure they continue to water, however. I've been doing this for 4 years. It's a calculated risk and it works for the good of ALL water usage. It's just that my neighbor's are paying for it.
