Woodland phlox makes an excellent groundcover, provides soil stabilization, and attracts birds, bees, and butterflies.
FIRST IMPRESSIONS: Phlox divaricata is a lovely spring ephemeral wildflower that forms foot tall clumps. Plants have semi-evergreen oval or lance shaped deep green leaves. In early spring, foliage is crowned by loose clusters of showy pinkish-lavender or icy blue flowers. Woodland phlox is a fine groundcover for woodlands or shade gardens with moist well drained soil.
HABITAT & HARDINESS: Phlox divaricata occurs in eastern North America in Quebec and Ontario, south to Vermont and Florida and west to South Dakota and New Mexico.
This species is indigenous to rich deciduous woodlands, open moist to slightly dry woods, seasonal floodplains, stream banks and open areas near woodland paths.
Plants are hardy from USDA Zones 3-8.
PLANT DESCRIPTION: Phlox divaricata is a mounding rhizomatous perennial groundcover.
Green or purplish stems are erect or decumbent and may be sprinkled with sticky glandular hairs.
Leaves are elliptical or lance shaped with smooth edges and blunt or pointed tips. Blades average 1-2” length and ½” width. They are sessile and are peppered with short fine hairs.
The leaves are opposite and arranged in widely spaced pairs. Each set of blades is situated at a right angle to those above and below.
Fertile stems terminate in showy rounded flower cymes. Florets are fragrant with 5 flat, often notched, blue-violet to rosy-lavender petals that flare from a narrow tube.
Blooming occurs in early to mid-spring for about a month. Small inconspicuous oval seed capsules follow.
Plants grow 12-18” tall with an equal spread. They gradually form colonies from short rhizomes and spreading leafy stems that root at the nodes.
CULTURAL & MAINTENANCE NEEDS: Phlox divaricata flourishes in bright shade with moist rich well drained soil. Plants tolerate clay loam, sand, acid or alkaline pH, heat, drought, part sun and dry shade.
Plants are fairly pest resistant but need good air circulation to prevent issues with powdery mildew.
LANDSCAPE USES: This is a good Groundcover for a Wildlife Garden or Shade Garden. Plants are also used as Butterfly Nectar Plants or as part of a Grouping or Mass Planting. In mild climates attractive rosettes provide Winter Interest. Phlox divaricata has Showy Blooms and is appropriate for Cottage Gardens, Water-wise Landscapes, Low Maintenance Plantings and Perennial Borders.
COMPANION & UNDERSTUDY PLANTS: Try pairing Phlox divaricata with Aquilegia canadensis, Carex albicans, Carex plantaginea, Heuchera americana 'Dales Strain', Dryopteris marginalis or Polystichum acrostichoides.
Phlox stolonifera has similar appearance and culture and could be substituted in some situations.
TRIVIA: Phlox divaricata provides valuable early season nectar for swallowtail butterflies, day flying sphinx moths (hummingbird moths and clearwing moths) and hummingbirds. The leaves and stems are somewhat unpalatable to deer but are often nibbled by rabbits.
Taxonomists recognize 2 varieties or subspecies. P. divaricata var. divaricata has flower petals that are shallowly notched at the tip and a range that extends east from the Great Lakes. P. divaricata var. laphamii has petals without notches and ranges west from the Great Lakes to the Great Plains and south into the Gulf Coastal Plain as far as the Florida Panhandle.
This is one of the only Phlox spp. to have fertile and infertile stems. The flowering fertile shoots die back after producing seed. Infertile non-flowering stems persist through the growing season and fuel the following year’s growth.
For more information on this plant, visit the USDA PLANTS Database: http://plants.usda.gov/java/profile?symbol=PHDI5