Symphyotrichum laeve: Smooth Aster

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Introduction

Smooth aster is a herbaceous perennial with an upright, branching growth habit that reaches a height of 3 feet and spread of 4 feet (Figure 1). The gray-silver leaves of smooth aster have a fine texture and clasp the stem, and lavender daisy-like flowers appear on the plant in the late summer through fall (Figures 2 and 3). This plant is an excellent option for pollinator gardens, as it will attract butterflies, bees, birds, and other pollinators. It is a late season bloomer and may reseed itself in the landscape. This Florida native plant is drought tolerant and adapts to a variety of site conditions. It is well suited in a naturalized area or pollinator garden, edging in landscape beds, or may be utilized as cut flowers.

General Information

Scientific name: Symphyotrichum laeve

Previous scientific name(s): Aster laevis (synonym)

Pronunciation: sim-fy-oh-TRY-kum LAY-vey

Common name(s): smooth aster, smooth blue aster, smooth-leaf aster

Family: Asteraceae

Plant type: herbaceous, perennial

USDA hardiness zones: 4B through 8B (Figures 4 and 5)

Planting month for zone 7: year-round

Planting month for zone 8: year-round

Planting month for zone 9: year-round

Origin: native to Florida

Uses: mass planting; edging; attracts butterflies and other pollinators; cut flowers; naturalized area

Availability: somewhat available, may have to go out of the region to find the plant

Description

Height: 2 to 3 feet

Spread: 2 to 4 feet

Plant habit: upright, branching

Plant density: symmetrical habit with a regular (or smooth) outline and individuals having fairly identical forms

Growth rate: fast

Texture: fine

Use and Management

Smooth aster thrives when planted in full sun but tolerates partial shade. Full sun locations will encourage more prolific blooming. It is adaptable to a variety of soil conditions and is moderately drought tolerant. As this plant has an upright branching growth habit and rapid growth rate, some maintenance may be required. This plant performs well as edging in the landscape or in a group planting. It makes a nice component in a mixed border. Smooth aster is also a larval hostplant for the Pearl Cresent butterfly, and attractive to pollinators including butterflies, birds, and several species of specialized bees. The flowers of smooth aster can be cut for flower arrangements, as they last several days indoors.

Smooth aster is propagated by softwood cuttings or by division.

Design Use

To best showcase smooth aster, leverage its fine, gray-silver foliage and light blue-lavender flowers by creating strong visual contrast. Pair its cool tones with the warm golds of ornamental grasses or the deep burgundy of dark-leaved perennials to make the blooms pop, or set them against crisp white flowers for a clean, classic look. Texturally, you can either harmonize its delicate stems with other airy grasses for a soft, meadow-like feel, or contrast them against bold, broad-leaved plants to highlight their graceful form. For maximum impact, plant the aster in small drifts in the mid-to-back of the border, where its flowers can float above shorter plants against a solid evergreen backdrop. Placing these drifts near a pathway allows for close appreciation, while using a neat, low-growing edging plant will frame the aster's looser habit.

Pests and Diseases

No pests or diseases of major concern.