The lone voice of horticultural reason
“Watering my trees and shrubs is covered, because I have a lawn irrigation system”
Boy, the number of times I’ve heard that one. I’ll keep it short: If you have a built-in lawn sprinkler system and you have just planted shrubs and trees in and around the lawn, you don’t have anything covered. A lawn sprinkler system typically means pop-up heads on a timer; they come up once a day or every other day and spray water in arcs around your lawn. This is not a good way to water shrubs and trees.
Lawn sprinkler systems get the foliage of the plants wet, four to seven times a week, for one thing. That encourages fungal disease. Second, trees and shrubs need a good, long, deep soaking every four to five days the first month after planting, and once a week after that, the first year, then every two weeks the following years—a far different schedule than that of lawns.
Trees and shrubs watered by a lawn irrigation system get too much water, too often, in the top two to four inches of soil, and next to nothing deeper than that. They suffer, struggle, and quite often die.
A lawn irrigation system is for lawns, period. Disconnect or redesign your lawn irrigation so that it skips your shrubs and trees. Then water the shrubs and trees by hand, or have installed a second system, using soaker hoses, on a different timer, and run that through the tree/shrub areas.
The Renegade Gardener