More Lessons Learned? Or, Why I Worry About The Dogwood Trees....Plus, Birch

The first three photos are the red dogwood tree, then the white, then the birch. I guess all of them are more thirsty than I knew. Maybe if I take care of them, despite the dogwoods position in the full sun, sunniest spot I have, they would be ok?

The internet (SFGATE) says:

• Irrigate a dogwood tree once or twice weekly during the summer and autumn months. Thoroughly soak the ground to 6- to 12-inches deep so that the water reaches the soil beneath the root-zone area. The shallow roots can't tolerate dry soil conditions.
• Apply a 3- or 4-inch layer of mulch around your dogwood tree to help maintain soil moisture. Extend the mulch layer about 8 to 10 feet from the base of the trunk, but keep the material about 4 inches away from the trunk itself. Replenish the mulch when needed to maintain the layer's initial depth.
• Water your dogwood trees with a garden hose rather than a sprinkler system. Sprinklers get the leaves too wet, which makes the foliage susceptible to moisture-related diseases such as anthracnose, powdery mildew and gray mold. Avoid getting the foliage wet when watering.

So, I guess, an unusually hot and dry May/June without doing those things could be an issue.