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. These flowers, each with five small flat petals, will vary greatly in their blue tones. Some petals will be light purple, violet, violet-blue, and even a lighter blue; still, others will be rosy lavender, pale pink, or white. Many but not all of the phlox's leaves will be covered in sticky glandular hairs that produce protective oils for the plant.
|Botanical Name||Phlox divaricata|
|Common Name||Woodland phlox, wild sweet William, wild blue phlox|
|Plant Type||Herbaceous perennial|
|Mature Size||1 ft. or slightly taller, similar width|
|Sun Exposure||Dappled shade|
|Soil Type||Moderately moist, well-drained, and fertile|
|Bloom Time||April or May|
|Flower Color||Light purple, violet, violet-blue, light blue, rosy lavender|
|Hardiness Zones||3 to 8 (USDA)|
|Native Area||Eastern North America|
Woodland Phlox Care
Woodland phlox is a perfect 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.
Woodland phlox grows in flecked patches of 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. If you live elsewhere but find this perennial attractive, consider trying to naturalize it in your landscape. The species name divaricata translates from the Latin as "spreading," but it is not considered an invasive plant.
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.
Woodland phlox grows best in checkered shade so do not try to grow it in full sun unless you live in a cool climate. Find a location in your landscaping that will best mimic the flower's natural habitat, providing this perennial with, at most, filtered sunlight.
Try to mimic the rich, moist soil that you'd find in woodland conditions. The soil should also drain well for best results. The plant, however, is very adaptable and will tolerate dry, clay soil, especially when it is established.
Keep the soil of woodland phlox evenly moist. 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.
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 b working compost into the ground around your plant annually in spring. Or, compost with leaf mold if you want to go the extra mile.
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.
Many people prefer the popular violet-blue color and find it in the cultivar, 'Blue Moon.' But there are several other cultivars, including a white one: 'Fuller's White.'
Lightly cut back stems after the plant flowers to clean up the garden's appearance. Prune in the late summer and fall if you do not want the plant to reseed. Be aware that if phlox stems flop over onto the ground, there will be leafy shoots that will actually begin to root at the nodes and grow into the soil which will increase the colony's spread.
To propagate or reinvigorate, divide these perennials in spring. Woodland phlox is easy to propagate by seed, division in spring or early fall, or take stem cuttings in spring, or root cuttings in early fall. It rarely grows as a potted plant because it's more of a ground cover.
- Remove lower leaves from cuttings.
- Dip ends into hormone powder for faster growth.
- Plant in rich, moist soil.
- Keep in a space with indirect sunlight.
- Cuttings will root in four to eight weeks.
- When either spring or fall cuttings root, transfer outdoor in the spring after the threat of frost has gone.
How to Grow Phlox From Seed
Phlox seeds usually need to be purchased because getting them from the plant proves a challenge. Sow seeds indoors two months before the start of spring.
- Put them in rich, moist soil.
- Keep them in a dark spot that stays around 65 degrees Fahrenheit.
- Keep them evenly moist.
- Seedlings appear at the beginning of spring.
- Plant seedlings outdoors after the threat of frost is gone.
Overwintering is not a necessity with phlox but mulching before the first frost will protect the plants in colder regions.
Common Pests & Diseases
A problem in growing woodland phlox 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.