Move Over, Mums! Asters Are the Fall Flower Everyone Wants
Move over, mums! There’s another beautiful autumn bloomer that belongs in your garden.
Not only do asters look fabulous, but they also provide late season food for pollinators such as butterflies and bees. They bloom from late August until well into October or first frost, when most of the rest of your garden is winding down for the season.
Asters have daisy-like flowers with white or yellow centers and petals varying from white to blue to lavender to pink. They’re equally at home in a cutting garden, cottage garden or border, and they also can be grown in containers. These long-lived perennials tend to grow taller in rich soils, but they adapt to most soil types.
Asters native to North America belong to the Symphyotrichum and Eurybia genera, or classification, while those from Europe and Asia come from the genus Aster. But all types use the same common name.
Asters are considered a “keystone plant,” which means they support many different kinds of wildlife. For example, deer and rabbits like to graze on the plants, while hungry birds such as dark-eye juncos, American goldfinches, and American tree sparrows enjoy the seeds.
Why Trust Us?
I'm a garden writer with more than 15 years of experience growing houseplants, herbs and edibles, and landscape plantings. My houseplant collection includes more than 60+ plants, while my garden includes new annuals, perennials and shrubs that I trial for performance and reliability. Asters are one of my favorite perennials for late season color and for the large number of wildlife and insect species they support.
Aster Basic Info:
Common Name: Aster, Michelmas daisy
Botanical Name: Aster spp., Symphyotrichum spp. and Eurybia spp.
Plant Family: Asteraceae
Type of Plant: Perennial in USDA zones 4 to 8
Native Origin: Europe, Asia, North America
Sun Exposure: Full sun to part shade
Mature Size: 6 inches to 8 feet tall, 1 to 3 feet wide
Toxic to pets: No
Where to Plant Asters
Some varieties of asters are taller than many other perennials. We recommend placing them at the back of a border, or deeper into a garden space. This also allows you to cover the lower foliage—which can get scraggly—with other perennials in the foreground, such as sedum, heuchera, or perennial geraniums.
How to Plant Asters
You can grow asters from seed, but it will take several years before the plants mature enough to bloom. If you'd like quicker results, opt for plants purchased from reputable nurseries.
To plant, dig a hole about twice the width of the container. Ease the plant out of its pot, rough up the surface of the root ball with your gloved hand, then place it in the hole and backfill.
Then tamp down gently to eliminate air pockets, and water well. Space aster plants a few feet apart, based on the variety’s mature size (read the plant tag or description so you know what you’re buying).
How to Care for Asters
Asters are easy-to-grow with the right conditions:
Light Needs of Asters
Most asters need full sun, which is considered 6 or more hours of direct sunlight per day. They will tolerate some shade, but they bloom best in sun.
Soil Needs of Asters
Asters grow in most soil types, but they do not like soggy or heavy clay soils.
Water Needs of Asters
Asters like soil that’s consistently moist. If they don’t bloom well, you may not be giving them sufficient water.
Temperature Needs of Asters
In warmer climates, give asters some afternoon shade. Otherwise, they can tolerate full sun. They are not sensitive to humidity levels.
Fertilizing Asters
Asters do fine without fertilizer and adapt to poor soils; in fact, too much will shorten bloom times.
Pruning Asters
It’s not necessary to prune asters but you can shape them to keep them neat and compact. Pinch back the tops of stems from spring to about early summer, which encourages branching. You can deadhead, or remove spent blooms, if you like, to encourage reblooming, too. (Learn more about deadheading plants here.)
Common Pests and Problems
Some types of asters are vulnerable to powdery mildew. Prevent this disease by planting far enough apart and thinning out plants (remove about a third of the stems to the ground) in the spring to provide good air flow.
Propagating Asters
The easiest way to propagate asters is to divide plants as they become too large for a planting area. Dig up the entire clump in early spring when they first appear, divide into sections and replant immediately.
You can also simply cut some plants off the edge of a section using a shovel—just make sure to get the roots. Water transplants well until they are established, which takes several weeks.
Types of Asters
New England Aster (S. Novae-angliae) has pretty daisy-like purple flowers; reaches 3 to 6 feet tall
Bigleaf Aster (Aster macrophyllus) grows even in poor soils and tolerates some shade; reaches 1 to 2 feet tall
Smooth Aster (Aster laevis) blooms well into November; yellow centers turn red later in the season; reaches 2 to 4 feet tall
Aromatic Aster (S. oblongifolium) is a native plant that has sky blue flowers and blooms into November; reaches 1 to 3 feet tall
White Wood Aster (Eurybia divaricata) has showy white flower clusters and heart-shaped leaves; grows 3 feet tall
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