Growing Asters

How to Plant, Grow, and Care for Aster Flowers

Aster Flowers
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Asters are daisy-like perennials with starry-shaped flower heads. They bring delightful color to the garden in late summer and autumn when many of your other summer blooms may be fading.

There are many species and varieties of asters, so the plant’s height can range from 8 inches to 8 feet, depending on the type. You can find an aster for almost any garden at garden centers in autumn!

The plant can be used in many places, such as in borders, rock gardens, or wildflower gardens. Asters also attract bees and butterflies, providing the pollinators with an important late-season supply of nectar.

Planting

Choosing and Preparing a Planting Site

  • Asters prefer climates with cool, moist summers—especially cool night temperatures. In warmer climates, plant asters in areas that avoid the hot mid-day sun.
  • Select a site with full to partial sun.
  • Soil should be moist but well-drained, and loamy.
  • Mix compost into the soil prior to planting. (Learn more about soil amendments and preparing soil for planting.)

Planting Asters

  • While asters can be grown from seed, germination can be uneven. You can start the seeds indoors during the winter by sowing seeds in pots or flats and keeping them in the refrigerator for 4 to 6 weeks to simulate winter dormancy. Sow seeds one inch deep. After 4 to 6 weeks, put the seeds in a sunny spot in your home. Plant outside after the danger of frost has passed. (See local frost dates.)
  • The best time to plant young asters is in mid- to late spring. Fully-grown, potted asters may be planted as soon as they become available in your area.
  • Space asters 1 to 3 feet apart, depending on the type and how large it’s expected to get.
  • Give plants plenty of water at the time of planting.
  • Add mulch after planting to keep soil cool and prevent weeds.

Aster monarch butterfly
Asters are highly attractive to pollinators, especially bees and butterflies.

Care

How to Grow Asters

  • 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 you receive less than 1 inch of rain a week, remember to water your plants regularly during the summer. However, many asters are moisture-sensitive; if your plants have too much moisture or too little moisture, they will often lose their lower foliage or not flower well. Keep an eye out for any stressed plants and try a different watering method if your plants are losing flowers.
  • Stake the tall varieties in order to keep them from falling over.
  • Pinch back asters once or twice in the early summer to promote bushier growth and more blooms. Don’t worry, they can take it!
  • Cut asters back in winter after the foliage has died, or leave them through the winter to add some off-season interest to your garden.
    • Note: Aster flowers that are allowed to mature fully may reseed themselves, but resulting asters may not bloom true.
  • Divide every 2 to 3 years in the spring to maintain your plant’s vigor and flower quality.

Pests/Diseases

Susceptible to:

Harvest/Storage

Recommended Varieties

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.

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 on the smaller side.
  • 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 may 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.

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.

See more aster variety recommendations.

Wit & Wisdom

  • Asters, one of September’s birth flowers, were once burned to ward off serpents.
  • The name “aster” comes from the Ancient Greek word for “star”—a reference to the plant’s star-shaped flowers.
  • Thanks to the aster’s late bloom time, they are sometimes called “Michaelmas daisies.” Michaelmas is a holiday that occurs annually on September 29.

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Reader Comments

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There are many varieties of

There are many varieties of asters and most bloom in the fall. Alpine asters bloom in the spring. If your asters bloomed when you planted them they will probably not bloom again this year. Find out what type of asters you have.

This is paresh from gujrat,

Submitted by paresh on

This is paresh from gujrat, India.
I planted marigold and dutch roses in my farms. I am planning to plant some asters as well. I have no information of planting asters. Can anyone give me any details????

Just plant in loamy soil and

Submitted by Jash on

Just plant in loamy soil and fertilize before blooming. they are pretty forgiving!

Asters are tall, (and bloom

Submitted by condi on

Asters are tall, (and bloom in fall), so you may want to put them in the back of the garden, or on the north side of it, so as to not shade the other plants. Asters like sun, at least partial. For bushier, shorter, bloomier plants, cut back to 8" in early summer (whenever that is in India, in Wisconsin, cutback time is june 8). You may want to cutback only the ones in front. Then the ones in back will bloom first. Other growing details are above in article!

It I'd Febuary and I ordered

Submitted by vickie Burkhart on

It I'd Febuary and I ordered some dwarf asters and they are in a box with small amount of dirt , roots and the greenery is dryed up now but roots look ok. When can I plant these now or later this spring ???? But I am afraid if I don't they will die before then. I live in ky and its giving snow and cold temps. When and what should I do???? Please

You can plant the asters in a

The Editors's picture

Submitted by The Editors on

You can plant the asters in a container with soil. Keep them indoors until you can plant them outside after the weather warms up. Keep the soil moist.

Help please!I purchased quite

Submitted by stellabridger on

Help please!I purchased quite a few small growing asters from a mail order co. last year and foolishly planted them in a bunch hopefully to provide a big display of flowers in my quite large garden. They didn't bloom at all last year but grew rapidly together into a tight shrub.I have just divided them into 4 medium size shrubs and transplanted them around the garden. Is this correct and how can I ensure they bloom next Summer/Autumn?

Asters are sturdy plants and

The Editors's picture

Submitted by The Editors on

Asters are sturdy plants and transplant well. Keep the transplants watered and make sure they get enough sun (full sun is ideal).

I'm very new at planting. How

Submitted by Crickett Eads on

I'm very new at planting. How do I plant Peter Blue Aster . I need to plant everything in pots due to roots in mt yard. its Nov 6th and i don't know how to plant it . Help!

Plant asters anytime after

Submitted by Chris McNeely on

Plant asters anytime after the last spring frost. They'll bloom in late summer and fall.

Uuuggghhhh... I bought 5

Submitted by chris Rumbelow on

Uuuggghhhh... I bought 5 Asters from Home Depot 3 weeks ago... but haven't had time to plant them in the ground. It now Oct 30th... is it too late to get them in the ground here in Madison, WI?
The 7 day forecast shows nothing below 32 degrees for the next seven days. Highs in the mid 40's & 50's if that helps.

If it is too late... how do I winter them indoors?

Chris

Hi Chris, It's OK to plant

The Editors's picture

Submitted by The Editors on

Hi Chris,
It's OK to plant your asters now. Plant them as soon as you can and keep them watered until the soil freezes. Add a little mulch around the plants to keep the moisture in. See our planting advice on this page.

I have too many Aster plants

Submitted by Brenda Law on

I have too many Aster plants in my garden.They seem to be bullies and very prolific. What is the best way to keep the plant under control and from taking over?

The best way to keep them

The best way to keep them under control is to pull up the unwanted ones. You can also cut the tops off and then keep the area mowed or cover the area with black plastic.

I purchased some Believer

Submitted by L Spurgeon on

I purchased some Believer Asters for a buck, 1/2 of the plant is dry and brittle, 1/2 green. Will the dry and brittle part return to normal next growing season?

If it is one plant and half

If it is one plant and half is still alive the plant will come back next year. Add some compost around the plant before winter.

Hello and thanks for this

Submitted by ChristineJ on

Hello and thanks for this site, love it! Q- I just gathered up seeds from my dry brown Aster blooms. I want to grow Aster plants from the seeds.....now what?

See info above about planting

The Editors's picture

Submitted by The Editors on

See info above about planting aster seeds!

Can annual asters be kept

Submitted by brett on

Can annual asters be kept alive indoors until spring

Perennial asters last through

The Editors's picture

Submitted by The Editors on

Perennial asters last through the winter in the right zone with lots of mulch, but annual asters will die at the end if their season. You can try to extend the season outdoors with a cold frame to protect from frost or bring indoors but the declining light may end their life cycle.

I just purchased 4 beautiful

Submitted by Kathy DeL on

I just purchased 4 beautiful purple Asters. There are bees all over them, that I understand. What I don't get is, why are there so many flies on the plant?

Some flies are active

The Editors's picture

Submitted by The Editors on

Some flies are active pollinators of sedum, too, not just the bees. Unless you see the plant being chewed on (suggesting a pest), don't worry. At this time of year, plant sources may be low so all the pollinators will visit the asters.

Actually, those may not be

Submitted by Keith D. - PA on

Actually, those may not be flies...they could be Mason Bees. Some Mason Bees look, at first glance, just like flies. But Mason Bees are very gentle, rarely sting and are GREAT pollinators!

My large, late blooming

Submitted by Eric Lagerberg on

My large, late blooming asters have been a subtle, light blue for the last several years. This year they are a bright crimson with a smaller flower. Is this transformation common? The blue was prolific and stunning. The crimson is not so impressive.

We've never known our asters

The Editors's picture

Submitted by The Editors on

We've never known our asters to change color.
Asters do have anthocyanin, a pigment compound. It looks bright pink in acidic soil environments and reddish-purple in neutral soil. It's possible that the acidity of your soil could affect color. You could have a soil test.
Of course, asters do come in many colors from white and pink to lavender, purple, and blue. What most often happens is that you have a hybrid and the more dominant color starts to take over. This is the more likely explanation.

I have grown some lovely

Submitted by Denise trask on

I have grown some lovely Astes from seed, now in full flower but have noticed that some of the leaves are curled up with small green caterpillars and black "eggs" inside them. What can I treat them with?

There are many caterpillars

There are many caterpillars that eat aster foliage, including beet armyworms, cabbage loopers, carnation leafrollers, corn earworms, etc. For better or worse, the best control is to handpick the caterpillars off your asters with tweezers. Wear gloves to prevent stings or rashes. Drop the pests into a bucket of soapy water as you pluck. You can apply Bacillus thuringiensis but only when they are very young and you really want to ensure it's a "pest" destroying your plant not a beneficial bug. You could take a sample to your county cooperative extension office.

What fertilizer works best on

Submitted by Mariana Guerrero on

What fertilizer works best on asters so they can bloom more and better?

According to the UMass

According to the UMass cooperative extension, "Use a 150 to 200 ppm N constant feed program with a well- balanced fertilizer such as 15-16-17. Slow-release fertilizer can be used as top-dressing, but liquid fertilization may be needed as a supplement in case the fertility level drops, Asters are sensitive to high soluble salt levels. Injury is exhibited as root damage, leaf yellowing, and leaf drop."
We stop fertilizing when blooming begins.

My New England asters started

Submitted by Kansas gardener on

My New England asters started turning yellow with tiny spots on leaves,from the ground up a few weeks ago, now brown, disease or bugs?

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Growing Asters

Botanical Name Astereae
Plant Type Flower
Sun Exposure Full Sun, Part Sun
Soil Type Loamy
Soil pH Varies
Bloom Time Summer, Fall
Flower Color Blue, Pink, Purple, Red, White
Hardiness Zones 3, 4, 5, 6, 7, 8
Special Features Attracts Butterflies

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