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Symphyotrichum novi-belgii

new york aster

Asteraceae Eastern North America

Attracts Pollinators Attracts Butterflies Container Friendly

Native to North America

SunFull Sun – Part Shade

WaterMedium

HardinessZones 4–8

Overview

Symphyotrichum novi-belgii is an upright herbaceous perennial 24-48 inches (60-120 cm) tall, forming clumps that spread by short rhizomes to 18-24 inches (45-60 cm) wide. Smooth, branching stems carry narrow, lance-shaped leaves 2-5 inches (5-13 cm) long that clasp the stem at the base. From late summer into autumn the plant produces broad sprays of daisy-like flower heads 1-1.5 inches (2.5-4 cm) across, each with 30 or more narrow ray florets surrounding a yellow central disc. In the wild species the rays are blue to violet, while garden selections extend the range to pink, mauve, red, and white. The flowers are followed by small dry seeds tipped with pale bristles for wind dispersal. It grows naturally in damp meadows, ditches, and coastal marshes in eastern North America and has naturalized in Europe. A limitation is its susceptibility to powdery mildew, which disfigures the lower foliage in dry summers and crowded plantings.

Native Range

Symphyotrichum novi-belgii is native to eastern North America, from Newfoundland south to Georgia, typically in damp coastal and lowland habitats. It has naturalized across much of Europe, where it is grown and known as the Michaelmas daisy.

Suggested Uses

Symphyotrichum novi-belgii is used in herbaceous borders, cottage gardens, and naturalistic late-season plantings, often combined with ornamental grasses and other autumn perennials. It supplies nectar for bees and butterflies during autumn when few other flowers remain. Cut stems are used in fresh arrangements.

How to Identify

Recognized by upright leafy stems topped with broad clusters of blue to violet daisy flowers 1-1.5 inches (2.5-4 cm) across in late summer and autumn. The narrow leaves clasp the stem at their bases, separating it from Symphyotrichum novae-angliae, which has hairy stems and leaves that clasp more strongly. The numerous thin ray florets and yellow disc are typical of the genus.

Appearance

Size & Dimensions

Height2' - 4'

Width/Spread1'6" - 2'

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~8 weeks

Fall

Flowering runs from late summer into mid-autumn, roughly August to October. The flower heads open in succession over six to eight weeks, peaking in September. Bloom coincides with the Michaelmas period, the source of the common name.

Detailed Descriptions

Flower Description

blue to violet

Foliage Description

green

Growing Conditions

Sun Requirements

SunFull Sun SunPartial 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 Range5.5 - 7.5(Neutral)

357912

Soil Types

clay loam

Drainagemoist

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Time to Maturity

2-3 years

Care & Maintenance

Care Guide

Symphyotrichum novi-belgii grows in full sun to part shade in moist, fertile soil that does not dry out in summer. It tolerates a soil pH from about 5.5 to 7.5 and grows in clay or loam with steady moisture. Clumps benefit from division every two to three years to maintain vigor and reduce congestion. Air movement around the plants lessens powdery mildew, which is worse on dry, crowded specimens. Staking supports the taller stems in exposed sites. Plants die back to the ground in winter and regrow from the base in spring.

Pruning

Stems are cut back to ground level in late autumn or winter after they die down. Pinching the shoots once in early summer produces shorter, bushier growth with more flower stems. Deadheading spent flowers extends the display slightly and limits self-seeding.