How to Grow Asters: The Complete Aster Flower Guide

purple aster flowers in a garden
Photo Credit
Pixabay
Botanical Name
Aster spp., Symphyotrichum spp.
Plant Type
Flower
Sun Exposure
Full Sun
Part Sun
Soil pH
Varies
Bloom Time
Summer
Fall
Flower Color
Blue
Pink
Purple
Red
White
Hardiness Zone
3
4
5
6
7
8
Special Features
Attracts Butterflies

Also receive the Daily newsletter including gardening tips, weather, astronomical events, and more.

No content available.

Planting, Growing, and Caring for Asters

Catherine Boeckmann

Asters enliven the garden in late summer and early fall when many flower blooms fade—providing a late-season treat for bees, butterflies, and other pollinators! Plant these deer-resistant native perennials to keep the color going. Learn all about planting, growing, and caring for asters.

About Asters

Cold-hardy perennials with daisy-like flowers, aster flowers are the pollinator stars of the garden from late summer through fall. Growing 1 to 6 feet tall, depending on variety, these upright flowering plants bear cheerful, star-shaped flower heads ranging from purple to white to blue.

Even though there are more than 600 aster species, the two most commonly encountered asters in home gardening are the New England aster () and the New York aster (). Several years ago, the Aster genus was split into multiple genera. Aster now covers most European and Asian asters, while those native to North America belong to Symphyotrichum.

Some hybrid varieties are available in showy colors, yet “wild type” species native to your region are generally a wise choice for the ecologically minded gardener despite not being quite as flashy as the cultivated varieties in some cases. Learn more about recommended varieties further down this page.

Aster is versatile: Depending on the height, it’s suitable for borders, rock gardens, or wildflower gardens. As well as being a valuable pollinator plant for bees and butterflies, its tasty seed heads are sought by cardinals, chickadees, finches, nuthatches, and many other seed eaters.

According to the , “Any species or cultivars of this genus would be a lovely addition to any home garden. It may be planted in a container for use on a porch or patio. It will also add color to a cottage garden or border garden. Butterflies and bees will appreciate the flowers, particularly as summer is ending and the evenings are getting cooler.”

Read Next

Planting

Asters prefer areas with cool, moist summers and cool nights in sites with full to partial sun. In warmer climates, asters do not like the hot midday sun. Soil should be moist but well-draining and loamy. Wet clay soil will lead to root rot, and dry sandy soil will lead to plant wilt. Mix 2 to 3 inches of compost into the soil before planting. 

When to Plant Asters

  • The best time to put young aster plants in the ground is in mid- to late spring after the danger of frost has passed. (See local frost dates.)
  • Or, you can plant mature, potted asters when available at garden centers (typically in the late summer or early fall).
  • Asters can be grown from seed, but germination can be uneven. If desired, plant seeds in the fall or start them indoors in the winter. 

How to Plant Asters

  • When planting young aster plants outside in the spring, space them 1 to 3 feet apart, depending on the type and how large they’re expected to get.
  • Fully grown asters, such as those available in late summer or early fall, should be planted about 3 feet apart.
  • If planting seeds, sow 1 inch deep in pots or flats and refrigerate them for 4 to 6 weeks to simulate winter dormancy. This cold period will kick-start germination.
  • Water well, and spread mulch around the plants to keep the soil cool and prevent weeds.
purple Aster and monarch butterfly
Asters are highly attractive to pollinators, especially bees and butterflies.

Growing

  • Add a thin layer of compost (or a portion of balanced fertilizer) with a 2-inch layer of mulch around the plants every spring to encourage vigorous growth.
  • If less than 1 inch of rain falls weekly in summer, water regularly. But beware: Many asters are sensitive to too much or too little moisture. They will lose their lower foliage or not flower well. Watch for stress and try a different watering method if your plants lose flowers.
  • Stake the tall varieties to keep them from falling over.
  • Pinch or cut back asters by one-third once or twice in the early summer to promote bushier growth and more blooms. Don’t worry; they can take it! Do the Chelsea Chop!
  • In winter, cut back asters after the foliage has died, or leave them through the winter to add some off-season interest to your garden. Birds may munch on the seeds, too.
    • Note: Aster flowers that mature fully may reseed themselves. The resulting asters may not bloom true to their parent. (In other words, you may not get the same color flowers you planted initially!)
  • Divide every 2 to 3 years in the spring to maintain your plant’s vigor and flower quality.

Types

The most common asters available in North America are the New England aster (Symphyotrichum novae-angliae) and the New York aster (Symphyotrichum novi-belgii). Both of these plants are native to North America and are great flowers for pollinators. We recommend planting a native species of aster over a non-native species when possible, so talk with your local Cooperative Extension or garden center about which species are best suited to your area. Look for varieties with disease resistance.

North American Asters

  • New England asters (S. novae-angliae): Varieties have a range of flower colors, from magenta to deep purple. They typically grow larger than New York asters, though some varieties are smaller.
  • New York asters (S. novi-belgii): There are many, many varieties of New York asters available. Their flowers range from bright pink to bluish-purple and can be double, semi-double, or single.
  • Blue wood aster (S. cordifolium): Bushy with small, blue-to-white flowers.
  • Heath aster (S. ericoides): A low-growing ground cover (similar to creeping phlox) with small, white flowers.
  • Smooth aster (S. laeve): A tall, upright aster with small, lavender flowers.
  • Aromatic aster (S. oblongifolium): Multi-branched at the base, stiff upright stems, with lavender or pink flowers.

European/Eurasian Asters

  • Frikart’s aster (Aster x frikartii) ‘Mönch’: Hailing from Switzerland, this mid-sized aster has large, lilac-blue flowers.
  • Rhone aster (A. sedifolius) ‘Nanus’: This aster is known for its small, star-shaped, lilac-blue flowers and compact growth.

Harvesting

Cut asters for flower arrangements when blooms are just beginning to open. Vase life is 5 to 10 days.

Asters have side shoots, which will continue to develop. These can be cut for indoor arrangements once they are the size you like.

Learn more about keeping cut flowers fresh.

Gardening Products

Wit and Wisdom

  • The name aster comes from the Ancient Greek word for “star”—a reference to the plant’s star-shaped flowers.
  • Asters are called Michaelmas daisies because they bloom around September 29, the ancient feast day of St. Michael, and a quarter day, marking the transition to autumn. Learn more about Quarter Days!
  • Asters, one of September’s birth flowers, were once burned to ward off serpents.

The asters twinkle in clusters bright, 
While the corn grows ripe and the apples mellow. 
- Celia Thaxter

Pests/Diseases

Diseases: aster yellows; Botrytis blight; leaf spot, fungal; powdery mildew; rust; rot, Rhizoctonia root and stem, white smut, Fusarium wilt, Verticillium wilt.
Pests: aphids, foliar nematodes, slugs and snails, Tarsonemid mites.

Flowers
About The Author

Catherine Boeckmann

Catherine Boeckmann loves nature, stargazing, and gardening so it’s not surprising that she and The Old Farmer’s found each other. She leads digital content for the website, and is also a certified master gardener in the state of Indiana. Read More from Catherine Boeckmann
 

More Like This

Comments

Anonymoud (not verified)

10 years 1 month ago

I bought a beautiful aster. It was on a table at a nursery marked perennial sale. Very full and covered in flowers. It even had a hoop around it to keepit contained. The flowers are very puffy and kind of look more like mums. I'm hoping it's a perennial variety. They were only marked as andreas asters. Any insight on whether they are likely perennial or annual and if they might self seed would be great. Thankyou!

We are not familiar with Andreas asters but most asters are perennial. They do selfseed if you leave the faded flowers on the plant.

D. Campbell (not verified)

10 years 1 month ago

I bought 8 Blue Dragon asters Labor Day weekend while visiting family in Virginia (zone 6b) and promptly planted them in a slope flower bed at my home in North Carolina (zone 7b). The asters had many buds and blooms when I bought them, but every one of them has presumably died within 2 weeks of planting (they are brown and crispy looking). I did notice some snail "ooze" on them within the first couple days of planting so I put out snail repellant around each of the plants. They are planted on a slope with clay soil that gets partial sun.

My questions are: What did I do wrong? And will they come back next year?

Donna S (not verified)

10 years 1 month ago

So I bought some asters earlier this year and left them in the pot. They are beautiful! I'm not sure if I should leave them in the pots and just cut them back and then plant in the spring OR do I plant them now and cut back.
Thanks!

This happened to me too! I planted with very good organic garden soil. At first the wilted . I watered them and 3 hours later they were perky and upright. But now thd lower leaves are brown and dying. I'm going to try planting them in pots with drainage rather thN the ground. I got bee balms at the same time which have sturdier stalks and similar lookig flowers and they are kicking butt! Super sturdy , upright and seem to just endure a lot more. I'm going to switch out the Astros for more bee balm
In the garden and nurse the 3 a stirs back to health . Maybe ur soil is thd problem. In OH it's like clay

If you have a perennial aster (versus annual), we would cut them back to 6 inches after they bloom.
You could transplant the aster into the garden for the winter as long as it's six weeks before the ground freezes. 
Or, you could literally plant the container in the ground. This is a bit riskier. Tip: Plant the pot at a slight tilt so it doesn't acculate water at the top and drown itself when snow thaws. Finally, you can store the aster in an unheated garage.
Either way, you'll want to give it a nice watering before the ground freezes.

MistaBloom (not verified)

10 years 2 months ago

Transplanted 10 inch potted Asters after Labor Day. The root ball of each plant required me to dig the hole about 8 inches deep x 10 inches wide and returned the displaced soil to fill in around the planting. With adequate drainage, my initial watering was supplemented with basic plant food followed by daily watering applied as a mist from a garden hose.
Assuming I did everything correctly, why do the flowers within each planting (after 2 weeks) appear to be drying out? Plenty of afternoon sun and nightly temps no less than 60 degrees. The Mums that I planted are doing terrific (so far ) and they were planted under the same conditions. What went wrong and is this symptom of poor timing or a case of my deadheaded Aster without a bloom?
Signed :(( Discouraged novice planter

Check the soil about 2 inches below the surface to see if it is moist. If not the plants need more water. Add mulch around the plants. Asters like cool temperatures and will do better when the night temperatures drop below 60.

mbr (not verified)

10 years 2 months ago

"Last year, purchased and planted several potted "daisy like" asters, bearing the "annual aster" tag. Some were blue, and some purple. Since I do not care for the pin cushion looks of mums, I was delighted to find those beautiful daisy looking flowers with the yellow centers., even though they were annuals. I am in Nebraska, and was a bit surprised when they came up in the spring, again, and bloomed this fall. My issue? They are full and compact, with a profusion of purple and blue flowers. However, they no longer present with a daisy like appearance. They resemble the full, rounded flower of a mum, with no yellow center. I retained the marker, left in the ground from last year, to confirm that they were indeed the same flower. I have no mums planted in this flower bed. Any idea what happened?

Dennis McClure (not verified)

10 years 2 months ago

how can i tell if the astors that i just bought are perennial or annual. I still have the label from the plant but it does not specify either annual or perennial?