Woodland Phlox
Delicate Blue Spring Flowers
Woodland phlox (Phlox divaricata) is an herbaceous perennial plant native to the woodlands, stream banks, and shady meadows of eastern North America. From late spring to early summer, clusters of fragrant lavender-blue blossoms rise on slender stems above the loose clumps of foliage. The flowers create a delicate carpet of blue color, and provide an early source of nectar for spring butterflies.
This phlox is a low-maintenance plant and thrives in rich, moist, well-drained soil. It prefers partial to full shade, making it an excellent choice for woodland gardens, rock gardens, or as a natural ground cover. With minimal care, it will readily naturalize, forming an expansive colony over time.
Combine woodland phlox with other spring-blooming, shade loving plants like Bleeding Heart (Dicentra species), Astilbe, or Siberian bugloss (Brunnera macrophylla). Plant with Christmas ferns (Polystichum acrostichoides) and Lenten roses (Helleborus species) for a contrast in leaf shapes and textures. Let it naturalize and weave around the base of taller shade perennials like Goatsbeard (Aruncus dioicus) or Black Cohosh (Actaea racemosa).
Woodland phlox can occasionally suffer from powdery mildew. To prevent this fungal disease, ensure plants have good air circulation and cut back stems when flowering has finished. Spider mites can be a problem, especially when planting in hot, dry areas.
Is Woodland Phlox (Phlox divaricata) Invasive?
Woodland phlox is not considered an invasive plant in the United States. It is native to eastern North America, and typically coexists harmoniously with other native plants in its natural habitat. However, it's important to note that in certain situations, woodland phlox can become aggressive and potentially crowd out other desirable plant species in the garden. This is more likely to occur if the conditions in the landscape closely mimic the plant's natural habitat of partial to full shade and cool, moist, rich soil. Woodland phlox spreads by stolons (above-ground, creeping roots), making it very easy to thin out and keep in check.
Is Woodland Phlox Deer-Resistant?
Deer will eat woodland phlox, and it is not considered a deer-resistant plant. Woodland phlox is rated as “occasionally severely damaged” by Rutgers University on their list of Landscape Plants Rated by Deer Resistance. If you are gardening in an area with heavy deer pressure, consider planting a deer-resistant ground cover for shade, such as sweet woodruff (Galium odoratum) or Allegheny spurge (Pachysandra procumbens). Rabbits are also quite fond of woodland phlox and can nibble plants down to the ground.
Cultivars of Woodland Phlox
‘Blue Moon’ has violet blue flowers atop green foliage, and is known for being a reliable performer. Flowers are larger than the straight species.
‘Pink Ridge’ is a vigorous grower with fragrant pink flowers.
According to the Mt. Cuba Center’s research, other popular cultivars like ‘Clouds of Perfume’, ‘Fuller’s White’, ‘May Breeze’, ‘Blue Dreams’ and ‘Plum Perfect’ are unreliable and prone to powdery mildew. Stick with the straight species or one of the more reliable performers like ‘Blue Moon’.