perennialN. America Native

Frost Aster

The Story

Plant Bio

Symphyotrichum pilosum is an erect, stiffly branched herbaceous perennial native to North America, forming a bushy, shrub-like mound up to five feet tall. In fall, the plant produces dense branching arrays of small, daisy-like flower heads with white ray florets surrounding yellow centers that age to reddish-brown.

The species features alternate, narrow leaves and stems covered in soft white hairs that create a hoary appearance, though the hairless variety pringlei remains smooth. It spreads through a woody crown, short rhizomes, and prolific self-seeding, making it an aggressive colonizer of open, disturbed soils.

Uses & Benefits:

Produces a massive, cloud-like display of small white flowers in late summer and fall when many other perennials have finished blooming.

Tolerates poor, dry, and salted soils, making it highly effective for stabilizing roadsides, slopes, and disturbed garden areas.

Serves as a critical late-season nectar and pollen source for native bees, butterflies, and beneficial wasps, and acts as a larval host for the Pearl Crescent butterfly.

Essentials

At a Glance

Plant Type

Perennial

Height

60"

Width

48"

Light

Full Sun, Partial Sun

Zones

4, 5, 6, 7, 8, 9

Water

Low to Medium

Humidity

Medium to High

Lifespan

Perennial

Native To

North America

Toxicity

Non-toxic

Bloom period

Late summer – Fall

In flower about 4 months of the year

Planting

How to Grow

Plant in a location that receives at least six hours of direct sunlight daily to ensure strong stems and maximum flowering.
Select a well-drained site with sandy, loamy, or clay soil, avoiding areas where water pools or remains saturated.
Water regularly during the first growing season to establish a deep root system, after which the plant is highly drought-tolerant.
Leave dead stems standing through winter to provide structural interest and nesting sites for native bees, then cut them to the ground in early spring.

Pro Tip

Pinch or cut back stems by one-quarter to one-third in late spring to prevent floppy, leggy growth; pruning after mid-July removes developing flower buds and ruins the fall display.

Keep It Thriving

Care Guide

Do

Pinch back stems in late spring to encourage a bushier habit.
Provide adequate spacing between plants to maximize air circulation and reduce powdery mildew.
Cut back old stems in early spring before new growth emerges.

Don't

Do not apply heavy fertilizer, which causes weak, floppy growth and increases disease susceptibility.
Do not prune the plant after mid-July, as this removes the autumn flower buds.
Do not plant in poorly drained, heavy clay soils where water stands.

Seasonal Care Calendar

Task	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Divide
Pest Check
Pinch
Spring Cleanup

Watch Out For

Pests & Diseases

Common Pests

Common Diseases

In the Garden

Landscape Uses & Companions

Landscape Uses

Meadows and prairiesPollinator gardensRoadside plantingsErosion control on dry slopesLate-season borders

Companion Plants

Solidago speciosa Schizachyrium scoparium Echinacea purpurea

Multiply

Propagation Methods

Good to Know

Common Questions

Frost Aster questions

What zones can Frost Aster grow in?

Frost Aster is hardy in USDA Zones 4–9. Inside that range it survives winter in the ground; outside it, grow it as an annual or a container plant you protect.

Is Frost Aster deer resistant?

Yes — Frost Aster is rated deer-resistant. Deer typically pass it over, though extreme hunger can override any plant's defenses.

When does Frost Aster bloom?

Frost Aster typically blooms in late summer through fall. Exact timing shifts a week or two with your zone — Sow's bloom calendar maps it to your garden.

Does Frost Aster need full sun?

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

Is Frost Aster drought tolerant?

Yes — once established (usually after the first full season), Frost Aster handles dry spells with minimal watering. Water deeply its first year to build the root system that makes that possible.