perennialN. America Native

Smooth Phlox

Phlox glaberrima

The Story

Plant Bio

Phlox glaberrima is an upright, clump-forming herbaceous perennial native to moist meadows, low woods, and riverbanks across eastern and midwestern North America. Stiff, unbranched stems bear smooth, lance-shaped dark green leaves and terminate in dense panicles of tubular pink to reddish-purple aromatic flowers.

Unlike many garden phloxes, this species features completely hairless, glossy foliage that exhibits strong natural resistance to powdery mildew. The long corolla tubes produce abundant nectar specifically adapted for long-tongued pollinators and hummingbirds throughout late spring and early summer.

Uses & Benefits:

Produces vibrant panicles of pink to reddish-purple flowers on smooth, clean stems.

Offers higher powdery mildew resistance than most tall garden phlox species in wet soils.

Provides vital nectar for butterflies, long-tongued native bees, sphinx moths, and hummingbirds.

Essentials

At a Glance

Plant Type

Perennial

Height

48"

Width

18"

Light

Full Sun, Partial Sun

Zones

4, 5, 6, 7, 8

Water

Medium to high

Humidity

High

Lifespan

Perennial

Native To

Eastern and Midwestern United States

Toxicity

Non-toxic

Bloom period

Late spring – Mid summer

In flower about 3 months of the year

Planting

How to Grow

Select a site in full sun to light shade with rich, moist, organic soil.
Space plants 12 to 18 inches apart to maintain air circulation around stems.
Water deeply upon planting and maintain consistent soil moisture throughout the root zone.
Apply a 2-inch layer of organic compost or bark mulch to retain moisture and keep roots cool.

Pro Tip

Ensure soil remains consistently damp and well-oxygenated, as stagnant, oxygen-deprived water causes root rot despite the plant's high moisture tolerance.

Keep It Thriving

Care Guide

Do

Keep soil consistently moist, especially during peak summer heat.
Deadhead spent flower panicles to prolong blooming and limit unwanted self-seeding.
Provide good air circulation around plants to minimize disease risks.

Don't

Do not allow soil to dry out completely during dry spells.
Avoid overhead watering late in the day to minimize leaf moisture duration.
Do not plant in oxygen-starved, stagnant bogs with poor water movement.

Seasonal Care Calendar

Task	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Deadhead
Divide
Fertilize
Spring Cleanup
Winter Prep

Watch Out For

Pests & Diseases

Common Pests

Common Diseases

In the Garden

Landscape Uses & Companions

Landscape Uses

Rain gardensMoist perennial bordersNative plant gardensPollinator gardensMeadow plantings

Companion Plants

Physostegia virginiana Eutrochium purpureum Iris versicolor Lobelia cardinalis

Multiply

Propagation Methods

Good to Know

Common Questions

Smooth Phlox questions

What zones can Smooth Phlox grow in?

Smooth Phlox is hardy in USDA Zones 4–8. Inside that range it survives winter in the ground; outside it, grow it as an annual or a container plant you protect.

Is Smooth Phlox deer resistant?

Not reliably. Deer may browse Smooth Phlox, especially tender spring growth — plan on repellents or fencing where pressure is high.

When does Smooth Phlox bloom?

Smooth Phlox typically blooms in late spring through mid summer. Exact timing shifts a week or two with your zone — Sow's bloom calendar maps it to your garden.

Does Smooth Phlox need full sun?

Smooth Phlox does best in full sun to part shade. In hot climates, afternoon shade keeps blooms fresher longer.