The lone voice of horticultural reason
“Water newly planted container trees and shrubs once a week”
Running into more and more research and evidence that the old once-a-week theory is myth. It used to be every two weeks, also myth. Water your newly planted container (and BB) shrubs and trees every five days, for the first month they are in the ground.
Makes sense. Container trees and shrubs are watered every day at the wholesaler, and at the retail nursery. The soil in the container is usually very well drained. The plants grow to depend on that constant moisture. If you water only once a week (or every two weeks) after planting, it leads to violent transplant shock.
This is for the first month. After 30 days, water shrubs and trees once a week, for the entire first season, and once a week the next season, if the specimens were planted in later fall.
The Renegade Gardener