Asters are daisy-like flowers that bloom in late-summer and early-fall. They come in a wide variety of colors and sizes, are easy to grow and bloom predictably and reliably. Asters attract pollinators with their bright colors and are disease and deer resistant.

On this page: Basics | Planting | Aster Care | Pictures | Design Tips

ASTER BASICS

Western Aster, Symphyotrichum ascendens, growing in Grand Teton National Park in western Wyoming. Photo by: B Brown / Shutterstock.

Zones:

3-10; varies depending on species and cultivar.

Flower color:

Colors are diverse, ranging from white and pastel blues and pinks, to hybrids of deep scarlet and purple.

Bloom time:

August through October; varies depending on species and cultivar.

Height/spread:

Most asters range from 1 to 4 feet in height, with some growing as tall as 5 or 6 feet and some staying as small as 6 inches. Their width typically ranges from 1 to 3 feet.

Types of aster:

According to the Chicago Botanic Garden, there are approximately 250 types of asters, many of which are native to North America.

Here is a list of the most common garden asters:

  • New England (Symphyotrichum novae-angliae)
  • New York (Symphyotrichum novi-belgii)
  • Aromatic aster (Symphyotrichum oblongifolium)
  • Heath aster (Symphyotrichum ericoides)
  • Smooth aster (Symphyotrichum leave)
  • Calico aster (Symphyotrichum lateriflorum)
  • Wood aster (Eurybia divaricata)

Other, less common, types include alpine aster, California aster, tatarian aster, heart-leaved aster, big leaf aster, sea aster, short’s aster, crooked-stem aster, Frikart’s aster, Italian aster, and East Indies aster. China aster (Callistephus chinensis), which belongs to the same plant family as the asters discussed here, is actually an annual.

PLANTING ASTERS

When:

Asters can be planted anytime from spring through fall. In warm areas, avoid planting during the heat of the summer. In cool areas, plant no later than early fall so the roots have time to develop before freezing temperatures arrive.

Soil:

All types of soil, but most prefer well-drained, organically rich soil. Learn more about preparing your soil here: Garden Soil 101.

Exposure:

Full sun, tolerates light shade, likes cooler summer temperatures.

Spacing:

Depending on which asters you’re planting, they’ll need to be spaced 1 to 4 feet apart.

Containers:

Asters can be planted in containers using a lightweight potting mix. Make sure your pot has a drainage hole and that there is easy access to water nearby. Some people even grow potted asters indoors.

CARE REQUIREMENTS

Water:

Once asters are established, they require little watering, unless conditions have become unusually dry and the plants show signs of stress. New York aster (Symphyotrichum novi-belgii) cultivars have shallow roots and may need more frequent watering during the summer, especially when planted in free-draining soils. Keep soil moist, but not saturated. Mulching to reduce water loss is an important strategy for preventing disease.

Pruning:

Pinching back stems, or deadheading, several times before mid-July helps to control plant height, promote bushiness, and encourages blooming through the entire season. Leave a few wilted blooms at the end of the season if you want your asters to self-sow. Learn more about pinching and deadheading here: Pruning Garden Shrubs and Perennials.

Staking:

Taller stemmed varieties may require staking.

Fertilizing:

Some gardeners say a layer of organic mulch will supply all the nutrients asters need, while others suggest a light application of an organic fertilizer at the start of their growing season. Do not apply fertilizer once your asters have started blooming as it may shorten the bloom time.

Dividing:

Whether you’re dividing to control the size of your asters or to propagate them, do it in spring just as new shoots are emerging. This will give them the entire growing season to overcome the shock. The frequency of division varies depending on the species and cultivar, but most asters will benefit from division every 2 to 4 years.

Pests and diseases:

In some areas foliar rust and powdery mildew can be a problem, while lace bugs pose the biggest threat when it comes to pest damage.

ASTER PICTURES

With such variety, it is easy to see why these autumn-blooming perennials take center stage in so many gardens. Here are a few varieties to explore:

Swipe to view slides

Photo by: Richard Bloom.

Aster ×frikartii ‘Mönch’

Zones 5-10
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One of the first hybrids by Swiss breeder Carl Ludwig Frikart (1918), this was named for one of three mountain peaks visible from his nursery. Lavender-blue flowers from late June through early October. The Pictons recommend pairing with Symphyotrichum novi-belgii ‘Saint Egwyn’.

Photo by: Clive Nichols.

Symphyotrichum oblongifolium ‘October Skies’

Zones 4-9
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Aromatic asters are heat- and cold-hardy—and derive their name from the light scent they produce when crushed. These make good companions for small shrubs and trees; particularly chrysanthemum. ‘October Skies’ has purple-blue flowers .75 inches across and reaches 18 inches high.

Photo by: Richard Bloom.

Symphyotrichum novi-belgii ‘Patricia Ballard’

Zones 4-8
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The reliably blooming bright purple-pink double flowers, 1.75 inches across, on branched sprays that grow up to 36 inches tall make ‘Patricia Ballard’ a good choice for the front or mid-border. Bred at Old Court Nurseries by Percy Picton in 1957.

Photo by: Richard Bloom.

Symphyotrichum novae-angliae ‘Purple Dome’

Zones 4-9
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One of the shorter New England asters, ‘Purple Dome’ produces branching sprays up to 24 inches tall. “This is a beautiful selection—naturally compact, floriferous, deep purple,” Jim Sutton says. “A dense grower with excellent mildew resistance.”

Photo by: Richard Bloom.

Aster 'Little Carlow'

Zones 4-8

Compact clumps will reach 20 inches across in 2 years, producing sprays up to 4 feet tall. Free-blooming flowers are about 1 inch across. These are popular in formal borders and meadows. “Contrast the dense sprays of this aster with textures from other plants,” suggest Helen and Paul Picton, co-authors of The Plant Lover’s Guide to Asters.

Photo by: Richard Bloom.

Symphyotrichum novi-belgii ‘Jenny’

Zones 3-9

Compact, bushy sprays and intense color mark this dwarf New York aster. Purple-red double flowers are 2 inches across with sprays up to 15 inches tall.

Photo by: Richard Bloom.

Symphyotrichum novi-belgii ‘Carnival’

Zones 4-8

Magenta flowers with yellow discs grow from late summer into autumn. Try it in gravel beds, borders, and informal gardens.

Photo by: Richard Bloom.

Symphyotrichum laeve ‘Calliope’

Zones 4-8

Also known as smooth blue aster, ‘Calliope’ is unique for its height and purple-tinted stems, making it a good choice for cutting. It grows to more than 6.5 feet high in good conditions. As such, say the Pictons, “it lends itself to more wild or naturalistic planting schemes.”

Photo by: Richard Bloom.

Symphyotrichum novae-angliae ‘Helen Picton’

Zones 4-8

This New England aster sports vibrant purple flowers, 1.5 inches wide, in large sprays atop upright stems to 48 inches tall. According to its namesake, “Swaths of perennial grasses . . . can be given an easy boost of color in mid-autumn with large clumps of this aster.”

Photo by: Steffen Houser/GWI.

Symphyotrichum ericoides ‘Lovely’

Zones 3-9

This bushy heath aster bears masses of small, soft pink flowers from late summer through mid-autumn. Tall stems and deep green foliage make ‘Lovely’ excellent for cutting. More drought tolerant than many asters, it also does well in full sun in a border or container.

Photo by: Richard Bloom.

Symphyotrichum novae-angliae ‘Herbstschnee’

Zones 4-9

The pale coloring—white flowers 1.75 inches across with pale green foliage—makes this unique among New England asters. Woody clumps produce sprays of compact branches up to 4 feet tall, so it’s best suited toward the back of a border.

Photo by: Richard Bloom.

Symphyotrichum novae-angliae ‘Mrs. S.T. Wright’

Zones 4-9

Profusions of lilac flowers, 2 inches across, bloom on sprays that grow up to 5 feet tall. This classic cultivar introduced by H.J. Jones in the UK more than 100 years ago is still popular among gardeners and butterflies alike.

Photo by: Richard Bloom.

Aster amellus ‘Veilchenkönigin’ (‘Violet Queen’)

Zones 3-10

Each branchy clump of this compact plant grows to about 16 inches high and 12 inches across. The small violet flowers (2 inches across) seem to glow with depth of color. The Pictons recommend placing these blooms next to structural grasses.

Photo by: Richard Bloom.

Symphyotrichum novi-belgii ‘Coombe Violet’

Zones 4-8

Reaching to 4 feet tall with a 2.5 foot spread, this aster may need staking to hold up the masses of violet-purple flowers with sunny yellow centers. Semi-double flowers are attractive to pollinators and look wonderful paired with grasses, as it is here with Calamagrostis ‘Karl Foerster’.

Photo by: Richard Bloom.

Symphyotrichum lateriflorum ‘Prince’

Zones 4-8

A bushy plant with petite, skyward-facing white flowers a half inch across, this mid-fall bloomer differs from other varieties in the deep coloring of its spring growth. The yellow discs of the flowers fade to purple. Spreads to about 12 inches across.

Photo by: Visions Pictures.

Symphyotrichum ericoides f. prostratum ‘Snow Flurry’

Zones 4-8

Heath asters tend to have a bushy habit, hairy stems, smaller leaves, and sparser ray florets than other asters. This aster sits just 4 to 6 inches above the ground and spreads to about 1 foot. White flowers about a half inch across create what looks like a blanket of mid-autumn snow. The Pictons recommend planting ‘Snow Flurry’ where it can cascade.

EXPERT DESIGN TIPS

Choose Contrasting Companions
Hardy ornamental grasses and substantial foliage plants such as Yucca, Carex, and coleus provide a sturdy backdrop for softer or brightly colored asters. For Jim Sutton of Longwood Gardens, his favorite sustainable companion plant is kale—especially ‘Lacinato’.

Go Big
Paul Picton, co-author of The Plant Lover’s Guide to Asters, says, “When planted en masse, billowing clouds of color will enhance and revive gardens at a time of year when most other flowers are fading.”

Planting asters alongside late-blooming perennials and grasses with strong color brings the autumn garden to life. Here, Aster ×frikartii ‘Mönch’ is joined by Rudbeckia fulgida ‘Viette’s Little Suzy’, Rudbeckia subtomentosa, Hydrangea ‘Annabelle’, Verbena bonariensis, Sedum ‘Matrona’, and Rosa ‘Rosemary Rose’, sweeps of Japanese forest grass, and black mondo grass. Photo by: Richard Bloom.

Put Them in a Container
Use a single bushy plant, or create a mini landscape with smaller asters and grasses. Picton suggests Aster cultivars, Symphyotrichum ericoides ‘Golden Spray’, and S. novi-belgii ‘Lady in Blue’ or ‘Rosebud’.

Pump Up the Color
Place asters next to other fall-flowering perennials, bulbs, and shrubs—or more asters. Mr. Picton recommends yellow and says goldenrods make wonderful companions for asters.

Vary Heights
Plant a mix of tall upright stems, low spreading shrubs, and everything in between. Used as a mid-border plant, medium-to-tall asters will pop out after the summer blooms have gone off. “Come September, they get a chance to shine,” Sutton says.

Place Properly
“Asters from Symphyotrichum novi-belgii, S. novae-angliae, S. ericoides, and S. cordifolium are happy in an open, sunny site in soil that doesn’t get too dry in summer,” Mr. Picton says. “Other species such as Eurybia schreberi will be happy to grow in dry shade. Warmer conditions might be tolerated by some of the true Aster found wild in Europe and Asia.”

Whether you want a pop of late-season color or an addition to your pollinator garden, Asters could be the answer.

Portions of this article were adapted from a piece originally written by Meg Ryan for our print magazine.

Last updated: September 4, 2018

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