IN heatwave conditions the aim is not to panic, plants are much tougher than most of us think. It is important that trees and shrubs are watered out at the drip line, not by the trunk.
Recently, I saw a gentleman watering a huge gum tree on the nature strip. He was pouring a bucket of water right at the trunk!
It may make him feel better, but it is useless for the health of the tree. Most hand watering is a complete waste of time, with water running off and never reaching the roots.
Imagine an umbrella with the handle the trunk and the water running off the opened top. That outer edge is the drip line similar to the tree canopy. For small trees make an earthen bank round the tree or shrub to hold at least three buckets of water at the one time, depending on the size of the plant.
If using a drip system in extreme conditions operate the system for one to two hours in the morning and repeat in the evening. This only needs to be done once a week and your plants should be fine. A drip system, which is the ideal way of watering, does not need to be turned on every day.
For example, hydrangeas flop in the daytime heat and bounce back next morning. Plants do not have to be watered every time you see the leaves wilt. There were possibly more plants lost during the drought from overwatering than under watering. All they need is a good deep soaking once a week.