Outsidepride Blue Phlox Ground Cover Plant Flower Seeds - 1000 Seeds Blue phlox makes an excellent annual ground cover plant in USDA Zones 3 - 10. This spreading and creeping phlox only reaches 10 inches tall. Grow Phlox in beds, at the front of borders, and intermix them with other flowers in informal plantings and cottage gardens. They are wonderful container plants and maintain well in water when cut. The genus Phlox itself is a fascinating one that grows from relatively high altitudes in the mountains to the low lands in the prairies and the plains. Sow 3 to 4 of these non gmo, heirloom seeds per garden plant you desire.