Phlox paniculata, Garden Phlox
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Perennials

Phlox paniculata

Garden Phlox

Polemoniaceae

Eastern and central United States (New York to Georgia, west to Kansas and Nebraska)

At a Glance

TypePerennial
HabitUpright
FoliageDeciduous
Height24-48 inches (60-120 cm)
Width18-24 inches (45-60 cm)

Growing Zones

USDA Hardiness Zones

3 - 8
Zone 3
Zone 4
Zone 5
Zone 6
Zone 7
Zone 8
These zones indicate the coldest temperatures this plant can typically survive.
Frost Tolerancehardy

Key Features

Attracts Pollinators
Attracts Butterflies
Attracts Hummingbirds
Fragrant (strong)
Native to North America
Maintenancemoderate

Overview

An upright, clump-forming perennial in the family Polemoniaceae, native to the eastern and central United States, growing in moist, open woodlands, meadow margins, and stream banks. Plants form sturdy, erect stems 24–48 inches (60–120 cm) tall bearing opposite, lance-shaped to oblong leaves 3–5 inches (8–13 cm) long. From July through September, the stems are topped with large, domed to rounded panicles 4–8 inches (10–20 cm) across composed of dozens of five-petaled flowers 0.75–1 inch (2–2.5 cm) across in white, pink, red, salmon, lavender, purple, and bicolors, many with a contrasting eye. The flowers are notably fragrant — sweet and clove-like — and attract butterflies and hummingbirds in quantity. Powdery mildew is a significant and common disease problem, particularly in areas with poor air circulation; selecting mildew-resistant cultivars is essential for reliable performance. Recommended resistant cultivars include 'David' (white), 'Robert Poore' (purple), and the 'Flame' and 'Fashionably Early' series. Non-toxic.

Native Range

Native to the eastern and central United States, from New York south to Georgia and west to Kansas and Nebraska, growing in moist, open woodlands, meadow edges, and stream banks in fertile, moist, well-drained soil in full sun to partial shade.

Suggested Uses

Planted in mixed perennial borders, cottage gardens, and cutting gardens at 18–24 inch (45–60 cm) spacing. The tall, fragrant, colorful panicles are a hallmark of mid-to-late summer borders. Combines well with ornamental grasses, rudbeckias, and echinacea. An outstanding cut flower — long-lasting and intensely fragrant. Prioritize mildew-resistant cultivars ('David', 'Robert Poore', 'Flame' series) for reliable garden performance.

How to Identify

Identified by upright stems bearing opposite, lance-shaped leaves and large, domed panicles 4–8 inches (10–20 cm) across of five-petaled, sweetly fragrant flowers in pink, red, white, lavender, or purple, often with a contrasting eye, blooming July–September. The combination of tall upright habit, large fragrant panicles in midsummer, and opposite lance-shaped leaves is diagnostic. Powdery white mildew coating on leaves is a common indicator of susceptible cultivars in humid conditions.

Appearance

Size & Dimensions

Height2' - 4'
Width/Spread1'6" - 2'

Colors

Flower Colors

white
pink
red
salmon
lavender
purple

Foliage Colors

green

Fall Foliage Colors

no change

Bloom Information

Bloom Period

~10 weeks
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SummerFall
Blooms July through September in zones 3–8, with most cultivars peaking in July–August. Individual panicles remain in bloom for 3–4 weeks; some cultivars have extended seasons into September. Deadheading spent panicles to the next lateral bud can prompt a second, smaller flush of bloom. Fragrance is strongest in the evening. In the Pacific Northwest, blooms reliably July–September with excellent flower quality in the cool summers.

Detailed Descriptions

Flower Description

white, pink, red, salmon, lavender, or purple; large domed panicles, often with contrasting eye; sweetly fragrant

Foliage Description

medium green, opposite, lance-shaped to oblong; susceptible cultivars show white powdery mildew coating

Growing Conditions

Sun Requirements

Full Sun
Partial Shade
Requires 4-8 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range6.0 - 7.0(Neutral)
357912
Soil Types
loamclay
Drainage
moist

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Time to Maturity

1-2 years

Care & Maintenance

Care Guide

Plant in full sun (minimum 6 hours) in moist, fertile, humus-rich, well-drained soil with a pH of 6.0–7.0. Good air circulation around plants is essential to reduce powdery mildew — space at 18–24 inches (45–60 cm) and avoid crowding. Water at the base; overhead irrigation promotes mildew. Apply 2–3 inches (5–8 cm) of mulch to retain moisture and regulate soil temperature. Divide every 3–4 years in early spring to maintain vigor and reduce mildew susceptibility. Choose mildew-resistant cultivars for best performance.

Pruning

Deadhead spent panicles by cutting to the next lateral bud or leaf axil to encourage a second flush of bloom. In midsummer, thin stems to 5–7 per clump to improve air circulation and reduce mildew risk. Cut all stems to ground level in fall after frost, or in late winter. Divide every 3–4 years in early spring: separate into small sections (3–5 shoots) and replant at 18–24 inch (45–60 cm) spacing.

Pruning Schedule

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summerfallearly spring

Maintenance Level

moderate

⚠️ Toxicity Warning

Non-toxic