This should help: https://www.gardeningknowhow.com/ornamental/trees/dogwood/caring-dogwood-trees.htm
Hi this is Peggy, hope this information helps you with your dogwood tree. Dogwood trees are so beautiful. Most dogwoods require supplemental water during summer and fall, especially during hot, dry spells. Forcare of flowering dogwood trees, regular watering once a week to a depth of 6 inches should suffice. However, adding a generous layer of mulch will help retain moisture, minimizing watering chores.Apr 30, 2019
Dogwood Care - How To Grow Dogwood Trees - Gardening Know How
Here's another resource for dogwoods....this is a great site with lots of info.