What hardiness zones is Aster spp. suitable for?

Aster spp. is suitable for USDA hardiness zones 3, 4, 5, 6, 7, 8, 9.

How much water does Aster spp. need?

Aster spp. has Medium water needs.

1 / 5

Perennials

Aster spp.

aster

AsteraceaeNorth America, Europe, Asia

At a Glance

TypePerennial

HabitUpright

FoliageDeciduous

Height6 inches–6 feet (15–180 cm)

Width1.5–4 feet (45–120 cm)

Growing Zones

USDA Hardiness Zones

3 - 9

Zone 3

Zone 4

Zone 5

Zone 6

Zone 7

Zone 8

Zone 9

These zones indicate the coldest temperatures this plant can typically survive.

Frost Tolerancehardy

Key Features

Attracts Pollinators

Attracts Butterflies

Drought Tolerant

Container Friendly

Native to North America

Maintenancemoderate

Overview

A large genus of flowering perennials in the family Asteraceae, now taxonomically split with North American species largely reclassified into genera including Symphyotrichum, Eurybia, and Doellingeria. Garden plants sold under the name Aster include both the remaining Old World species and North American natives under their historical designation. Plants range from 6 inches to 6 feet (15–180 cm) tall depending on species, with erect to spreading habits. Leaves are lance-shaped to ovate, typically 1–5 inches (2.5–13 cm) long, alternately arranged, and often rough-textured. Composite flower heads are daisy-like, 0.5–2 inches (1.3–5 cm) across, with yellow central disc florets surrounded by 9–35 narrow ray florets in white, pink, lavender, or purple. Bloom occurs primarily late summer to fall, September through October in most zones. Plants spread by rhizomes and self-seed; some species can become aggressive in moist, fertile soils. Powdery mildew is common on lower foliage in summer, particularly on Symphyotrichum species in humid regions.

Native Range

The genus as broadly defined spans North America, Europe, and Asia. North American asters (now largely reclassified as Symphyotrichum and related genera) are native to prairies, open woodlands, roadsides, and moist meadows throughout Canada and the United States. Old World Aster species are native to Europe and Asia, including alpine and subalpine habitats.

Suggested Uses

Commonly planted in perennial borders and meadow gardens at 18–36 inch (45–90 cm) spacing depending on species. Valuable late-season nectar source for migrating monarch butterflies and other pollinators. Aggressive spreading species require division every 2–3 years to prevent them from crowding neighboring plants.

How to Identify

Identified by daisy-like composite flower heads with yellow disc centers surrounded by narrow ray florets in white, pink, lavender, or purple. Leaves are alternate, lance-shaped to ovate, often with rough or hairy texture. Bloom time is late summer to fall, distinguishing them from similar spring-blooming composites. Stems are often branched in the upper portion.

Appearance

Size & Dimensions

Height6" - 6'

Width/Spread1'6" - 4'

Colors

Flower Colors

white

pink

lavender

purple

yellow

Foliage Colors

green

Fall Foliage Colors

no change

Bloom Information

Bloom Period

~6 weeks

Fall

Blooms August through October in zones 3–8, with peak bloom typically in September. In zones 8–9, bloom may occur earlier in August and finish by late September. Individual flower heads last 1–2 weeks; plants carry multiple successive blooms over a 4–8 week period. Pinching stems back by one-third in June delays bloom by 2–3 weeks and produces more compact plants with increased flower count.

Detailed Descriptions

Flower Description

white, pink, lavender, purple with yellow centers

Foliage Description

medium to dark green

Growing Conditions

Sun Requirements

Full Sun

Partial Shade

Requires 6-8 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 Range5.8 - 7.0(Neutral)

357912

Soil Types

loamclaysand

Drainage

average

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Time to Maturity

2–3 years

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Plant in full sun in well-drained to average soil; most species tolerate a range of soil types but perform poorly in waterlogged conditions. Water regularly during establishment; established plants tolerate moderate dry periods but flowering is reduced without consistent moisture during bud set in late summer. Pinch or cut stems back by one-third in early to midsummer (before July 4 in the northern US) to reduce height and increase branching. Divide clumps every 2–3 years in early spring when the center begins to die out; discard the center and replant outer divisions 18–24 inches (45–60 cm) apart. Powdery mildew affects foliage cosmetically but rarely causes permanent damage; improve air circulation or select mildew-resistant cultivars.

Pruning

Cut stems back by one-third in June to control height and promote branching; do not cut back after mid-July as this removes developing flower buds. Cut plants to ground level in late fall after frost or in early spring before new growth emerges. Leave seedheads through winter to provide food for seed-eating birds; cut back in early spring before growth resumes.

Pruning Schedule

early springsummer

Maintenance Level

moderate

Container Growing

✓ Suitable for container growing

Minimum container size: 5 gallons

⚠️ Toxicity Warning

Non-toxic