wild blue phlox (Phlox divaricata)
moss phlox (Phlox subulata)
There are 71 native species of phlox across the US and Canada. Ten of them can be found in Maryland. These two are the ones I see most frequently in the Potomac Gorge, though I’m always on the lookout for others.
Wild blue phlox stands one to two feet tall, and likes the moist soils near the river. It’s often found growing near Virginia bluebells, though it seems to grow in the more uphill, drier areas as well.
Moss phlox stands only a few inches tall, and can mostly be found growing out of crevices and cascading over rocks.
As you can see, the flowers are almost identical in shape, but different colors. Moss phlox is more often pink, according to the books, but almost all the specimens I’ve found in the gorge are white.