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Symphyotrichum laeve

smooth blue aster

Asteraceae North America

Attracts Pollinators Attracts Butterflies Deer Resistant Drought Tolerant Container Friendly

Native to North America

SunFull Sun – Part Shade

WaterLow · drought-tolerant

HardinessZones 3–8

Overview

Symphyotrichum laeve is an upright, clump-forming perennial in the daisy family, native to much of North America, growing 2-4 feet (0.6-1.2 m) tall on smooth, often blue-tinged stems. It is set apart from many asters by its hairless, somewhat waxy blue-green leaves, which are lance-shaped, 2-5 inches (5-13 cm) long, and clasp the stem with rounded basal lobes. From late summer into fall the upper stems branch into open sprays of flower heads about 1 inch (2.5 cm) across, each with 15-30 pale blue to violet ray florets around a yellow center that ages to reddish-purple. The heads draw many late-season bees and butterflies, including migrating monarchs, and are followed by small seeds with pale bristles. It grows in dry to medium prairies, open woods, glades, and roadsides on well-drained soil. Tall stems can flop in rich soil or shade, and the plant spreads slowly by short rhizomes and self-seeding.

Native Range

Native across much of North America, from southern Canada through most of the United States, from the Atlantic coast to the Rocky Mountains and south to the Gulf. It grows in dry to mesic prairies, open woods, savannas, glades, and along roadsides on well-drained ground.

Suggested Uses

Used in native, prairie, and pollinator plantings, mixed and perennial borders, and naturalized meadows for late-season bloom. Its blue flowers and smooth foliage suit both wild and designed gardens on well-drained soil.

How to Identify

Look for an aster 2-4 feet (0.6-1.2 m) tall with smooth, hairless, blue-green leaves that clasp the stem and a waxy bloom that rubs off the foliage and stems. In fall it carries open sprays of blue to violet daisy flowers about 1 inch (2.5 cm) across with yellow centers. Its smooth, clasping, glaucous leaves separate it from the hairy-stemmed New England aster (Symphyotrichum novae-angliae).

Appearance

Size & Dimensions

Height2' - 4'

Width/Spread1'6" - 2'

Colors

Flower Colors

Foliage Colors

Bloom Information

Bloom Period

~6 weeks

Summer Fall

Flowering runs from late summer into mid-autumn, roughly August to October. The blue-violet heads open over four to six weeks and provide nectar and pollen late in the season for bees, butterflies, and migrating monarchs. Tufted seeds follow and disperse on the wind.

Detailed Descriptions

Flower Description

blue to violet with yellow center

Foliage Description

blue-green

Growing Conditions

Sun Requirements

SunFull Sun SunPartial Shade

Requires 4-12 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 Range5.5 - 7.5(Neutral)

357912

Soil Types

loam sand rocky clay

Drainagewell drained

Water & Climate

Water Needs

Low

Frost Tolerance

hardy

Time to Maturity

2-3 years

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Grows in full sun to part shade on dry to medium, well-drained soils and tolerates drought, heat, and poor, rocky ground once established. It is hardy in USDA zones 3-8 and needs little water after the first season. Rich soil and shade produce tall, floppy stems, while lean, sunny sites keep growth compact and upright. Pinching the stems in early summer lowers the mature height and reduces flopping. It spreads gradually by short rhizomes and self-seeding without becoming aggressive. Powdery mildew is less of a problem than on many asters, though crowding and damp air can still bring it on.

Pruning

Pinching or cutting the stems back by a third in late spring to early summer produces shorter, bushier plants with more flowers. Removing spent flower heads limits self-seeding. Old stems can be cut to the ground in late winter, or left standing to shelter overwintering insects.