Probably more than you have been.
One of the biggest mistakes people make is insufficient watering of their new plants. Most people think that because they have an irrigation system for their lawn that also sprays their plant beds, their trees and shrubs are recieving enough water. Lawn watering systems are programed to run one to three times a day for a short period of time, usually between 10 to 20 minutes. This soaks only the first few inches of soil, which is fine for lawns because of their shallow root systems.
Trees and shrubs need to develop deep reaching roots to allow them to withstand drought, extreme cold, and for trees, wind. Shallow watering encourages shallow weak roots. Trees and shrubs require slow, deep watering, reaching down well past the bottom of the root ball. They do best on a drip irrigation system or soaker hose. If that is not an option, place your hose at the base of the plant and turn on the water just enough to start it dripping, and just leave it for several hours. Depending on how hot the weather is, and how much rain we’ve gotten, this may need to be done as often as daily, or as little as twice a week.
Deep watering should continue until the plants go dormant in the fall. This will ensure that they are adequately hydrated until spring.