Woodland Phlox Plant Profile

Good Choice for Native Gardens in Dappled Shade

woodland phlox
David Beaulieu

Woodland phlox is an excellent native-plant option for gardens with dappled shade. It belongs to the Polemoniaceae family, as does Jacob's ladder (Polemonium caeruleum). Since this perennial grows wild, you may not be as familiar with it as you are with the commonly cultivated types of phlox, but it does belong to the same genus.

Botanical Name Phlox divaricata
Common Name Woodland phlox, wild sweet William, wild blue phlox
Plant Type Herbaceous perennial
Mature Size 1 foot or slightly taller, with a similar width
Sun Exposure Dappled shade
Soil Type Moderately moist, well-drained, and fertile
Soil pH Neutral
Bloom Time April or May
Flower Color Light purple, violet, violet-blue, light blue, rosy lavender
Hardiness Zones 3 to 8
Native Area Eastern North America

How to Grow Woodland Phlox

Woodland phlox grows in dappled shade in its native woodlands in eastern North America. It is curiously absent from most of New England, though: It is native only to Vermont and Connecticut in that region.

Find a location in your landscaping for woodland phlox that will best mimic its natural habitat, providing this perennial with, at most, filtered sunlight. Do not try to grow it in full sun. Likewise, in the wild, woodland phlox is naturally fertilized when the leaf litter in the forest breaks down (becoming "leaf mold"). Keep it fertilized in your landscape with compost (or with leaf mold if you want to go the extra mile).

Make sure to supplement what rainfall the plant may receive—enough to keep the soil moist (but never waterlogged) at all times. An application of landscape mulch will help you retain moisture in the location that you have selected.

A problem in growing woodland phlox that is less easy to solve is the potential attack of powdery mildew on its leaves. As with any plant susceptible to powdery mildew (or to fungus attacks, in general), aeration (through spacing) can help. It can also help to give woodland phlox a haircut after it has finished blooming, since rampant growth can be an invitation to powdery mildew. 

To propagate or reinvigorate, divide these perennials in spring.

Light

Woodland phlox grows best in dappled shade.

Soil

Make sure that the soil drains well.

Water

Keep the soil of woodland phlox evenly moist.

Fertilizer

Work compost into the ground around your plant annually in spring.

How Woodland Phlox Looks, Smells, Behaves

Woodland phlox plant has fragrant flowers, which bloom in clusters. The leaves can be evergreen at the more southerly end of its range.

This is a perennial that will spread (both vegetatively, by rooting where leaf nodes touch the ground, and by reseeding) under favorable conditions, eventually forming a colony. Indeed, the species name of divaricata translates from the Latin as "spreading."

Uses in Landscaping for Woodland Phlox

If you live in eastern North America and seek blue flowers for a dappled-shade garden featuring native plants, then woodland phlox is an excellent choice. If you live elsewhere but find this perennial attractive, consider trying to naturalize it in your landscape. Given the right growing conditions, it can be a splendid plant for woodland gardens anywhere.

More generally, treat it as a flowering ground cover or edging plant, especially where you need color specifically for spring. A potential drawback of using it as a ground cover is that it does not stay as short as many of the more conventional ground covers.

Woodland phlox is known to be a plant that attracts butterflies. It is also considered a flower worth including in hummingbird gardens.

Varieties of Phlox

The various types of phlox plants are popular landscape plants. The common creeping phlox (Phlox subulata) is best if you want a low ground cover, although there is also another creeping phlox that is less well-known: P. stolonifera. Meanwhile P. paniculata 'David' and the other popular, upright, summer-blooming phloxes―which are considered "garden phloxes"―are taller.

Woodland phlox flowers vary greatly in color. Some are light purple, violet or violet-blue, others a lighter blue; still, others are rosy lavender. Many people prefer the violet-blue color and find it in the cultivar, 'Blue Moon.' But there are a number of other cultivars, including a white one: 'Fuller's White.'