Question
How often do I need to water my liquid amber trees which are approximately 17 years old, growing in clay soil?

Answer
Mature trees do not really need watering unless the weather is dry and the soil around the tree is dry down to the first couple of inches. Then you can water with 1 inch of water-place a pan under the tree and turn the sprinkler on and when the pan has 1 inch of water in it stop. Do this once a week if it does not rain.