Garden phlox is a clump-forming herbaceous perennial native to eastern US from Main west to Minnesota, south to Georgia and Louisianna where it grows in woodland clearings and borders, meadows, lightly shaded riparian areas, thickets, and moist roadsides. It is a member of the Polemoniaceae family that also includes Jacob’s ladder. Plants grow up to 4′ tall from a taproot and have smooth unbranched stems, sometimes with purple streaks, and bearing narrow dark green pointed leaves 4-7″ long. From mid summer to fall, terminal pyramidal panicles of fragrant flowers appear that are 4-8″ across. Each tubular flower is up to 1″ across has 5 spreading petal-like lobes that are pinkish lavender to white in the species. Numerous cultivars are available that vary in color, size, vigor, disease resistance, floriferousness, and attractiveness. Garden phlox does better in cool weather and may struggle in hot humid weather especially where evening thunderstorms are common because of its susceptibility to powdery mildew. In spite of its disease issues, it is an outstanding border plant because of the beauty of its flowers and its long bloom time of 6 weeks or more. The flowers are also attractive to butterflies and birds. Tall varieties may need staking. The genus name, Phlox, is the Greek word meaning flame and refers to the color of some varieties. The specific epithet, paniculata, comes from the Latin word panicula meaning tuft and refers to the inflorescence.
Type: Herbaceous perennial
Bloom: Pyramidal panicles of pinkish lavender to white flowers from mid to late summer, sometimes into fall
Size: 2-4′ H 2-3′ W
Light: Full sun
Soil: Fertile, moist, well-drained, slightly alkaline
Hardiness: Zones 4-8
Care: Water in the morning to aid in mildew control; deadhead to prolong bloom.
Pests and Diseases: Powdery mildew, root rot, phlox bugs, spider mites
Propagation: Seed, cuttings (cultivars may not come true from seed)
Companion Plants: Echinacea purpurea ( purple coneflower), Monarda fistulosa (beebalm), Rudbeckia fulgida var. fulgida (blackeyed Susan), Geranium ‘Roxanne’
Outstanding Selections: ‘Bright Eyes’ (pale pink with rose eye), ‘Laura’ (purple with white eye; mildew resistant), ‘David’ (white)