Q.can a dogwood tree survive in zone 8-9
I live in Paso Robles, CA. with hot, dry summers and cold 20 below winters. Lots of ground squirrels.
The USDA hardiness zones for flowering dogwood is 5 to 9 so you are right in the range. Dogwoods can survive temperatures as low as -20 degrees. Although they are tolerant of seasonal dry periods, they are not tolerant of severe drought. The inability to grow on extremely dry sites is attributed to their shallow root system. So, unless your region habitually encounters severe drought, you should be fine.
For more information on dogwood trees, please visit the following link:
https://www.gardeningknowhow.com/ornamental/trees/dogwood/caring-dogwood-trees.htm