Phlox Paniculata 'Katherine'

Garden Phlox Katherine, Tall Phlox

Phlox paniculata ‘Katherine’ is an upright herbaceous garden phlox grown for fragrant lilac-blue to lavender flowers with distinct white central stars, blooming in midsummer to late summer and sometimes into early fall. It forms a clump of green foliage on stiff upright stems, usually requiring little staking, and works well in perennial borders, cottage gardens, pollinator gardens, cutting gardens, and mixed sunny beds. Missouri Botanical Garden lists the flowers as lilac-blue with white central stars in terminal panicles up to 6–9 inches long.

Type: Herbaceous perennial
Mature Size: 18–24 in. wide × 2–3 ft. tall
USDA Zones: 4a–8b
Form: Upright, clump-forming perennial
Light: Full sun to part shade; best flowering in full sun with steady moisture
Soil / Water: Fertile, humusy, well-drained soil; medium, even moisture preferred
Bloom Time / Length: July–September; often 4–6 weeks
Wildlife: Fragrant flowers attract butterflies, bees, and hummingbirds

Features & Landscape Uses:
Lavender to lilac-blue flowers with white eyes, clove-like fragrance, upright stems, and soft pastel color make ‘Katherine’ useful for middle perennial borders, cottage gardens, pollinator beds, cutting gardens, and moonlight or pastel planting schemes. Chicago Botanic Garden describes it as having lavender flowers with white eyes in July and August and notes that it attracts butterflies and hummingbirds.

Care:
Plant in rich, evenly moist, well-drained soil with good air circulation. Water at the base during dry spells, mulch lightly to keep roots cool, and avoid overhead watering where powdery mildew is common. Deadhead spent flower clusters to keep the plant tidy and encourage continued bloom. Cut stems back after frost or in early spring, and divide crowded clumps every few years. Mt. Cuba noted that ‘Katherine’ had attractive lavender-and-white flowers but could decline in midsummer from drought stress and powdery mildew sensitivity, so consistent moisture and airflow are important. 

Plant type

Perennial

Height

2-3'

Width

18-24"

Hardiness zones

4–8

Sunlight

Full Sun, Partial Shade

Growth rate

Moderate

Bloom time

Early Fall, Fall, Late Summer, Summer

Flower color

Lavender, Pink, Violet, White

Leaf color

Green

Fall color

Green

Attracts

Bees, Butterflies, Hummingbirds

Soil

Humus rich, Moist well-drained

Landscape use

Accent Plant, Border, Mass Planting

Shape

Clump, Upright

Fragrant

Yes

Deer resistant

Yes

Drought tolerant

No