Spreading Phlox
 

Spreading Phlox-Phlox diffusa
Spreading phlox is a beautiful, primarily mat-forming perennial. It may occasionally be found with upright growth, but not exceeding 10 cm in height. Its leaves are green, and not sticky or hairy. They tend to be much softer to the touch than those of Hood's phlox. Leaf shape is acicular or needle-like, with a length of 5 to 20 mm, and a width of 1 to 2 mm.

The flowers are solitary and nearly sessile at the ends of the stems. The calyx is somewhat hairy, with flat membranes between the calyx ridges. The flowers are tubular, with the 5 petal lobes angled perpendicularly away from the tube. The tube is about 9-17 mm long, with the lobes being 5 to 9 mm long. Flower color is white, pink, or a light blue. The style is 2-4 mm long. One anther is found near the opening of the tube, two below its base, and an additional two just above the middle of the tube (at about the same height as the tip of the style and stigmas).

Spreading phlox is suitable for the front of flower borders or the rock garden. One should provide good drainage, perhaps a raised bed, and limit the intrusion of taller species that might out compete it. Cushions may extend to about 50-80 cm wide. It does survive the moist climate west of the Cascades fairly well.