Description & Overview

Sky Blue Aster is a versatile Wisconsin native that blooms in early fall, adding a nice pop of color to any flower garden with its pretty blue flower petals and yellow central disks. Naturally found in prairies, fields and open woodlands, Sky Blue Aster is hardy and can handle dry, rocky soils and even drought.

The botanical name was formerly known as Aster azureus but it was changed in 2021.

Core Characteristics

Category: Perennial

Wisconsin Native: Yes

USDA Hardiness Zone: to zone 3

Mature Height: 24-36 inches

Mature Spread: 18-30 inches

Growth Rate: Fast

Growth Form: Perennial

Light Requirements: Full Sun to Partial Shade

Site Requirements: Many soil types, Moderate to Dry Moisture

Flower: Blue with a Yellow Eye

Bloom Period: September-October

Foliage: Dark Green

Fall Color: Reddish

Urban Approved: No

Fruit Notes: Achene

Suggested Uses

A late bloomer that adds some color to a wildflower garden, native garden, or butterfly garden. Good addition to a naturalized prairie. Tolerant of drought and dry, rocky, or clay soil.

Adds some nice color to a fresh-cut flower arrangement.

Sky Blue Aster is a versatile Wisconsin native that blooms in early fall, adding a nice pop of color to any flower garden with its pretty blue flower …

Wildlife Value

Butterflies, bees, flies, skippers, beetles, and more. Bees of the Colletes and Andrena spp. specialize in aster flowers.

The larvae of beetles, leafminers, flies, aphids, moths, and walking sticks feed on foliage and flower parts.

Different birds and mice eat the seeds and/or leaves of Sky Blue Aster. Rabbits, deer, and groundhogs eat the foliage.

It should be noted that Sky Blue Asters and many other species from this group bloom in the latest parts of the season. They signal the end of the growing season and the beginning of winter. The pollen they provide at that time of year is key for the successful overwintering and carbohydrate storage in many insect species.

Asters are critical in providing monarch butterflies with much-needed nectar to fuel their journey south for overwintering. Learn more about how to attract monarch to your yard.

Maintenance Tips

After the initial establishment period, this plant is low maintenance. Spreads through rhizomes and seeds.

Sky Blue Aster is a versatile Wisconsin native that blooms in early fall, adding a nice pop of color to any flower garden with its pretty blue flower …

Pests/Problems

No serious diseases affect this plant. Powdery mildew and leaf spots are possible aesthetic issues with Sky Blue Aster but are not fatal.

Leaf Lore

Sky Blue Aster now goes by the scientific name Symphyotrichum oolentangiense. Formerly, it went by Aster azureus and Aster oolentangiensis. Aster means “star” in Greek.

Many different cultures have their own Aster origin stories. My favorite: In Greek Mythology, the goddess Astraia (aka Virgo) began to cry when she saw how few stars could be seen from earth, as her tears fell to the ground each one turned to an aster. In another version of the story, she tried to remedy the lack of stars by sprinkling stardust on the earth, asters began to sprout from the dust.

Companion Plants

Grows in open woodland, prairies, and on roadsides. Would look beautiful alongside Butterflyweed, Yarrows, Goldenrods, Woodland Sunflowers, Switchgrasses, and Common Witchhazel.

Sky Blue Aster is a versatile Wisconsin native that blooms in early fall, adding a nice pop of color to any flower garden with its pretty blue flower …
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Written by Julia Feltes