For added convenience electronic garden hose watering timers can be installed. This allows customers to automate the watering by programming the watering frequency, watering run times and watering start times. Normally the timers are installed right at the faucet and for customers that are concerned that their faucet has been used for the sole purpose of watering the trees, then a splitter can be installed right at the faucet and a timer can then be installed on one side of the splitter.
This will allow you to have a dedicated hose for the trees and a free hose attachment for other purposes. There are lots of different types of water timers on the market to choose from but a simple and affordable one is from RainBird (Model #1ZEHTMR)