Watering will encourage the main roots of trees, shrubs and groundcovers to develop in the deeper, cooler soil layers rather than at the surface where temperature and moisture levels can fluctuate too severely. As well it will encourage the root system to radiate down and away from the soil surface so that eh plants function over a wider area and will become more stabilized.
Planted area
Initially plants should be watered more frequently but only for a short duration as the roots are quite close to the surface. The frequency of the watering should be gradually decreased with the duration increased to encourage maximum penetration of the roots into the deeper soil.
Turf area
Turf areas should be watered at least once a day within the first 3-4 weeks, and possibly twice a day if required during extreme temperatures. Watering should be for a long enough period to ensure good soaking of the turf. After the first initial weeks of watering the roots will begin to extend into the topsoil layer below the turf, gradually reduce the frequency and increase the duration of watering to encourage the roots to grow into the topsoil. Once established, apply approximately 5-10 litres per week to lawn areas.

I hope this has helped you and you will tune in next week for an insight on Weeding.

Cheers,
Denis