All evergreen garden plants such as rhododendrons, boxwood, cherry laurel and coniferous trees are best planted or replanted in late summer.
Now the risk of damage by a long drought is much lower than in spring. And the plants have enough time to root sufficiently until winter comes. Good soil moisture achieves a faster contact with the ground and the roots to grow rapidly. Therefore one must pour vigorously 2 times per week.
Although the aboveground growth is completed, the roots are still active until frost - best condition for a good start next spring.