HARDINESS: Zones 3 to 9
PREFERRED SOIL pH: Slightly acid
PREFERRED SOIL TYPE: Fertile, moist
PREFERRED LIGHT: Partial shade
ATTRIBUTES: Petite plants; blue, white, or pink flowers; for beds, groundcover, edging
SEASON OF INTEREST: Spring
FAVORITES: P. divaricata 'Clouds of Perfume', 'Chattahoochee' for partial shade; 'Fuller's White', 'Sherwood Purple' for shade; P. subulata 'Candy Stripe' for sun
QUIRKS: Prefers slightly acid soil
GOOD NEIGHBORS: Candytuft, deciduous trees, pansies, spring bulbs, shrubs
WHERE IT GROWS BEST: Humus-rich soil in open woodlands
POTENTIAL PROBLEMS: Rare
RENEWING PLANTS: Lives many years; seldom needed if plants reseed
CRITTER RESISTANCE: Good
SOURCE: Bedding plants, division
DIMENSIONS: 6-12 in (15.2-30.5 cm) toll and equally wide
Woodland and Moss Phlox in the Landscape
The shady slopes of eastern North American woodlands harbor many native plant riches, including dainty spring-blooming phlox. Similar to the tall garden phlox only in the size and form of the individual blossoms, woodland phlox are small plants never more than 12 in (30.5 cm) tall.They grow into casual colonies, covering the ground and lighting up the shade with their blue, pink, and lavender blossoms. Some selections are fragrant, and all reappear each year with no effort on the part of the gardeners who grow them. Blooming begins in concert with daffodils, tulips, and other spring-flowering bulbs, and the plants all but disappear by the time summer heat arrives. In sites that become, deeply shaded after trees leaf out, hardy ferns make particularly good companions, hiding the thin, fading foliage of the phlox.
Several native species fall into the woodland phlox category, but the most widely planted one is blue phlox (Phlox divaricata), a matchless choice for open glens framed by tall shade trees. Moss phlox (P. subulata) is a related species with ground-hugging mossy foliage. This petite plant is typically grown on sunny slopes and completely covers itself with pink, white, or lavender blossoms in early spring.
In filtered shade, grow P. divaricata 'Clouds of Perfume', which forms 12 in (30.5 cm) tall plants covered with fragrant blue blossoms, or 'Chattahoochee', which has violet-blue flowers with magenta eyes. Where sun is more limited, try 6 in (15.2 cm) tall 'Fuller's White' or 'Sherwood Purple', or mix them for an eye-popping duet.
For sunnier areas, choose P. subulata. 'Candy Stripe' is remarkable for its pink-and-white flowers with perky magenta markings in the center of each little flower.
Set out plants in fall or spring in any soil that is well drained and has a neutral to slightly acid pH. Amend sand or heavy clay with organic matter before planting and water well when plants are in place. The shade-tolerant species usually face little competition from weeds, but you will probably need to pluck out invaders from new plantings of moss phlox.
After woodland phlox blooms in spring, let it shed seeds before clipping it back in midsummer. You can also cut down a large planting with the lawn mower, raising the blade to its highest setting to protect the basal growth. Leave the area undisturbed, and new growth will appear from fall through winter, ready to bloom next spring. Moss phlox needs no special care beyond fertilizing in early summer and occasional watering in severe droughts. It is less prone to insects and the fungal disease powdery mildew than its cousin, garden phlox.