Phlox paniculata 'Katherine'
Common Name: garden phlox
Type: Herbaceous perennial
Family: Polemoniaceae
Zone: 4 to 8
Height: 2.00 to 2.50 feet
Spread: 1.50 to 2.00 feet
Bloom Time: July to September
Bloom Description: Lilac blue with white central star
Sun: Full sun to part shade
Water: Medium
Maintenance: Medium
Flower: Showy, Fragrant
Attracts: Birds, Hummingbirds, Butterflies
Tolerate: Deer, Clay Soil, Black Walnut

Culture

Grow in moderately fertile, medium moisture, well-drained soil in full sun to light shade. Best in full sun. Prefers rich, moist, organic soils. Needs good air circulation (space well and thin out stems as needed) to help combat potential powdery mildew problems. Intolerant of drought and needs to be watered in dry spells. Avoid overhead watering however. Appreciates a summer mulch which helps keep the root zone cool. Remove faded flower panicles to prolong bloom period and to prevent unwanted self-seeding (cultivars generally do not come true from seed).

Noteworthy Characteristics

Phlox paniculata, commonly known as garden phlox, is native from New York to Iowa south to Georgia, Mississippi and Arkansas. It has escaped gardens and naturalized into areas beyond its original native range. In Missouri, it is typically found south of the Missouri River in moist or rich low woods, thickets, alluvial banks and gravel bars along streams and bluff bases (Steyermark). This is an upright perennial that grows in a clump to 2-4' tall and to 2-3' wide on stiff stems clad with conspicuously veined, opposite, pointed, elliptic, deep green leaves (to 4-6" long). Fragrant, tubular, pink-purple to white florets (to 3/4” diameter) are densely packed in large, tiered, domed terminal clusters (to 6-8") over a long July to September bloom period. Each individual floret has a long corolla tube and five flat petal-like lobes. Butterflies love the flowers.

A large number of garden phlox cultivars in flower colors including white, lavender, pink, rose, red and bi-color are available in commerce. Cultivars resistant to powdery mildew are often the best choices.

The genus name of Phlox is derived from the Greek word for flame.

'Katherine' is a garden phlox cultivar which typically grows in an upright clump to 2-2.5' tall. Fragrant, tubular flowers (1/2" to 1" diameter) with long corolla tubes and five flat petal-like lobes are lilac blue with white central stars. Individual flowers are densely arranged in large, terminal, pyramidal clusters (panicles to 6-9" long) atop stiff, upright stems which seldom need staking. Long mid to late summer bloom sometimes extends into early fall. Narrow, opposite, pointed, lance-shaped leaves (to 5" long). Good fresh cut flower.

Problems

Phlox is not always an easy plant to grow well. Powdery mildew and root rot can be serious problems. Spider mites and plant bugs can also be a problem, particularly in hot, dry conditions.

Garden Uses

Garden phlox is a staple of the perennial border. Mixes well with other perennials and provides long summer bloom. Regardless of flower color, garden phlox is attractive to hummingbirds and is a good selection for inclusion in a bird garden.