100 Red Scarlet Phlox Drummondii Flower Seeds Tested packed on 01/20/23, 80% Germ. Grow Zones: 3,4,5,6,7,8,9,10 Scarlet phlox flowers grow in tight clusters and add a stunning pop of color to dull landscapes. Phlox drummondii is also an edible flower, lending it's beauty to numerous cake and entree garnishing possibilities. Whether grown in pots or use as ground coverage, it is a great choice. Germinate indoors for 4 - 6 weeks, let them grow until well-established (usually in a couple of months) then move them outdoors into light shade to full sun. Phlox seeds germinate when the soil temperature is around 65 degrees, hence why we suggest starting them indoors. Phlox prefers a well-draining sandy soil and will self seed once fully grown.