These garden top choices do well in high humidity, one basis that they flourish in the southeast U.S. Humidity in the air enables to protect the Phlox plants from losing moisture and wilting. They don't do well with extraordinary temperature changes, in any case, which is the reason they're suggested uniquely for growing zones 4-8. Even though Phlox can be planted outside in zones 3 and 9, you may not get great outcomes from your endeavors.