Phlox divaricata aka Forest Phlox

Phlox divaricata is a perennial wildflower in the phlox family. Common names include woodland phlox and wild sweet William. It grows wild across eastern North America. Its range reaches from southern Ontario to Minnesota, Georgia and Louisiana. It lives in rich woods, along streams and near woodland paths. Plants also grow at woodland edges where light filters through trees.

This low plant forms clumps and mats of green leaves. Garden plants reach about 1–1.5 feet [0.30–0.46 m] tall. North Carolina State reports shorter plants, from 0.5–1 foot [0.15–0.30 m]. Published spreads reach about 1.7 feet [0.51 m]. Shoots creep across the soil and root at their nodes. This growth can form broad colonies over time. The green stems bear hairs and feel sticky. Leaves grow in opposite pairs and have smooth edges. Their shape ranges from lance-shaped to oval. Some leaves remain through winter.

Loose flower clusters rise at the tips of the stems. Each flower has a tube and five flat lobes. Flower colors include blue, violet, lavender, rose and white. The blooms have a light scent. Missouri records flowering from April through May. Chicago records a later season, from May through June. Bees, butterflies and hummingbirds visit the flowers. Capsule fruits appear from March through July, according to North Carolina State.

Partial shade suits this woodland plant, and it tolerates deeper shade. The RHS also lists full sun for UK gardens. It grows best in rich soil that drains well. Keep the soil evenly moist for healthy leaves. Dry soil can cause leaf decline and summer dormancy. A light mulch helps keep roots cool and holds moisture. Sources list sandy, loamy, chalky and clay soils. The RHS accepts acid, neutral and alkaline soil. Hardiness ratings are USDA zones 3–8 and RHS H5.

Use woodland phlox along shaded borders or in woodland gardens. Its shallow roots make it a cover around spring bulbs. It also suits rock gardens and areas left to naturalize. Plants may sow themselves where conditions suit them. Powdery mildew and leaf spot can damage the leaves. Spider mites pose a risk during hot, dry weather. Rabbits may browse the foliage, though sources report deer resistance. Cutting stems back after bloom can help limit mildew. PFAF lists no known food or medicinal uses. It also reports no known hazards, rather than proven safety.