Sky Blue Aster

Symphyotrichum oolentangiense

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

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
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.

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.


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.

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