Trees, like people, appreciate water during hot spells.
Poke a tool like a long screw driver into the soil near the tree. If the ground is rock solid, it’s time to water. If it’s wet or muddy hold off.
Many of a tree’s roots rest between 12-24 inches below the surface – so a long slow sprinkle of 1 to 2 inches of water should help reach these roots (unless it’s competing with lawn turf). Move the hose around the root zone, which reaches about 1.5 times the height of the tree, to cover the entire root system when watering.