Question WHEN IS THE BEST TIME TO PLANT CREEPING PHLOX? Answer Creeping phlox is a tough plant! You can plant it either spring or fall. If you plant it now, you will be able to enjoy it early spring when it flowers. Tags: CareDesignFAQProjects Related Questions How far apart should I plant my Endless Summer hydrangeas? Did cutting flowers last year in the fall to dry in vases cause my hydrangeas to not produce any flowers this year? My hydrangea blossoms are very large and are turning brownish and dropping some petals. Should I cut off the blossoms to encourage new blooms? Otherwise the plants appear healthy. My rose bush looks wilted.