Aster

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Botanical name: Aster

Plant type: Flower

USDA Hardiness Zones: 3, 4, 5, 6, 7, 8

Sun exposure: Full Sun, Part Sun

Soil type: Loamy

Soil pH: Varies

Flower color: Red, Pink, Purple, White

Bloom time: Summer, Fall

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.

The plant's height ranges from 8 inches to 8 feet, depending on the type. You can find an aster for almost any garden and they have many uses, such as in borders, rock gardens, or wildflower gardens. Asters also attract butterflies to your garden!

Planting

  • Asters prefer climates with cool, moist summers, especially cool night temperatures.
  • Select a site with full sun to partial sun.
  • Soil should be moist, well-drained, and average to humus-rich.
  • Plany asters in early- to mid-spring. Fertilize soil prior to planting.
  • While the plant 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. After 4 to 6 weeks, put the seeds in a sunny spot.
  • Set seeds one inch deep.
  • Many gardeners purchase a potted plant from the nursery.
  • Space asters 1 to 3 feet apart, depending on the type. 
  • Water plants in well. Add mulch after planting to keep soil cool and prevent weeds.If you're replanting shoots, use vigorous, young shoots to ensure best growth.

Care

  • Add a thin layer of compost with a 2–inch layer of mulch around the plants every spring.
  • 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 variesties in order to keep them upright and remember to pinch the young shoots to encourage bushiness.
  • Cut asters back in winter after the foliage has died.
  • Divide every 2 to 3 years in the spring to maintain your plant's vigor and flower quality.

Pests

  • Susceptible to powdery mildew, rusts, white smut, leaf spots, stem cankers, aphids, tarsonemid mites, slugs, snails, and nematodes. Choose disease-resistant varieties.

Recommended Varieties

  • King George (Aster amellus), for its large, violet–blue flowers
  • Silver spray (Aster cordifolius), for its pink-tinged white flowers
  • Nanus (Aster thomsonii), for its star-shaped, lilac–blue flowers

Special Features

  • Attracts Butterflies

Wit & Wisdom

Asters, September's flowers, were once burned to ward off serpents.

Free E-Card

Send this lovely e-card of a butterfly on asters to your friends and family.

Comments

I bought 6 Asters in the

By MichelleB214 on July 6

I bought 6 Asters in the spring - 2 white, 2 pink, 2 purple, all with yellow centres. Plants around 8" tall when I planted them.The flowers lasted a few weeks then died. The plants themselves are surviving, just, but don't seem to be growing at all & I'm afraid they might just die. Having read your site & other books they should flower in summer-autumn? They're planted in a full sun border in a more clay like soil, well drained. The leaves are getting nibbled by tiny slugs which 'm trying to keep under control. I fed them with powdered blood, bone compound which should be suitable for flowering plants. Can't think what else I should do - any suggestions?

There are many varieties of

By Almanac Staff on July 7

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,

By paresh

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

By Jash on June 20

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

It I'd Febuary and I ordered

By vickie Burkhart

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

By Almanac Staff

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

By stellabridger

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

By Almanac Staff

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

By Crickett Eads

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

By Chris McNeely

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

Uuuggghhhh... I bought 5

By chris Rumbelow

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

By Almanac Staff

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

By Brenda Law

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

By Almanac Staff

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

By L Spurgeon

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

By Almanac Staff

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

By ChristineJ

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

By Almanac Staff

See info above about planting aster seeds!

Can annual asters be kept

By brett

Can annual asters be kept alive indoors until spring

Perennial asters last through

By Almanac Staff

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

By Kathy DeL

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?

Actually, those may not be

By Keith D. - PA

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!

Some flies are active

By Almanac Staff

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.

My large, late blooming

By Eric Lagerberg

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

By Almanac Staff

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

By Denise trask

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

By Almanac Staff

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

By Mariana Guerrero

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

According to the UMass

By Almanac Staff

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

By Kansas gardener

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?

It sounds as if you do indeed

By Almanac Staff

It sounds as if you do indeed have an aster disease, probably leaf spot. Here is a helpful guide to diseases and management. You could always get a sample to your local cooperative extension or garden center as a next step in diagnosis.

This is the first year I have

By Karen Lucas

This is the first year I have had asters, they bloomed and now the blooms have died out, do I need to "deadhead" these??

You can prune asters back

By Almanac Staff

You can prune asters back spring growth early in the summer (late May or early June). A month later, you can trim the top growth again. This will delay bloom slightly but will cause the plants to bloom more, get less floppy, and grow in a bushier shape.
Try sheering the tops to see if you can get a second round of blooms?

Will making the soil more

By Sally Ibarra

Will making the soil more acidic help them be more bluish? Or is that for just certain plants?

We've never known asters to

By Almanac Staff

We've never known asters to change color. You can manipulate the colors of hydrangeas by the level of acid in the soil.

Production area of aster

By maletsau

Production area of aster flower in South africa

The Old Farmer's Almanac is a

By Almanac Staff

The Old Farmer's Almanac is a publication for readers of North America (U.S. and Canada). Unfortunately, we can not advise on South Africa.

How is the growth medium of

By maletsau

How is the growth medium of aster flower prepared

Just make sure the soil is

By Almanac Staff

Just make sure the soil is moist and drains well--not wet. Asters do not like "wet feet." Otherwise, asters are quite tolerant.

My Victoria Mathilde Asters'

By Barb Smiley

My Victoria Mathilde Asters' new growth leaves are much thinner than the ones close to the ground. This is their second season. Should I cut them back? Where do the flowers grow, near the larger leaves at the base of the plant or on the top of the new growth?

You've stumped us! This may

By Almanac Staff

You've stumped us! This may be a new variety and so may require special attention, if you are following the advice above and not getting satisfactory results.
Another option is to consult either (or both?) the source of the plant and your local agricultural extensive service.

My asters leaves start

By shirley hursh

My asters leaves start turning brown in early summer, starting at the bottom and gradually moving up the stem. They do this every year. Any ideas?

If the leaves turn yellowish

By Almanac Staff

If the leaves turn yellowish and then brown, it could be a pest. In our area, we have the lacebug appear in midsummer. Organic or synthetic insect sprays can be used for control. Speak to your county extension office or local nursery. Bring them a sample!

I have Aster Frikartii

By JamieBass

I have Aster Frikartii planted in a small roadside garden at the end of my yard. This is the second year I have tried to grow these along with several other perennials (Chrysanthemum Becky, Salvia May Night, Phlox Laura, Kalmeris Blue Star, Gaura lindheimeri and Hemerocallis Happy Returns). The daisy's and Gaura lindheimeri are doing great. The May Nights were doing okay but a couple have died. The Asters and Phlox Laura look yellow and stressed. I am not sure if it is from overwatering or too little water. I usually water that area when I water my grass which is every other day. The area they are planted is at the bottom of a slight slope as my yard slopes towards the road for drainage. The flower garden butts up against the curb so water cannot drain very well past that I point I am guessing....although I never see an accumulation of water there. I think I may be overwatering, but I am at a loss since the becky's and guara's are doing so well. I welcome any and all feedback. This is just my second year doing this.

Since this is your second

By Almanac Staff

Since this is your second year doing this, and presumably you had better luck in the first year, the first question that comes to mind is what's different?
Too much water could certainly be an issue, esp for the "yellow and stressed" plants. That's a fairly typical clue. Phlox do not like to be watered from overhead; it's better to water their soil. And, btw, they like a lot of water.
Other plants in your collection, such as salvia prefer well-draining soil—in fact, they can tolerate drought!
Putting plants with different moisture needs side by side and then treating them all the same (think water) will favor some and hurt others.
Finally, you think the water can not drain very well up against the curb...why not find out for sure? Dig around: Is this heavy soil or compost-y, aerated type that drains well?
Assess the soil, and then decide which plants can take it and which can not. Uproot the struggling ones and replant them into conditions they like/need...and you might all live happily ever after. ;-)

aster leaves have balls of

By Lois Morse

aster leaves have balls of what looks like spit on them is this a pest and what organic spray can be used to treat these? thank you

You have a spittlebug nymph

By Almanac Staff

You have a spittlebug nymph living under the foam. They will chew on the leaves and new buds but the damage is minimal. Early summer is when you will see them. A strong spray of water will knock the nymph to the ground or you can pick them off the plant. Invite lacewings and ladybugs to your garden. They are predators of the spittlebug.

We purchased asters last fall

By Mike Foukes

We purchased asters last fall and had to plant them quickly. It is memorial day weekend, we live 40 miles north of Detroit, can we replant them now to another area in the bed?
Thanks

Asters should be moved or

By Almanac Staff

Asters should be moved or divided in May as the new shoots emerge. You're still fine.

Pruning

By Anonymous

I know I have to cut my mums back by half in mid-summer. Should I prune back my aster too? Its our first year.

Instead of pruning the asters

By Almanac Staff

Instead of pruning the asters try pinching the tops of the stems for a fuller aster with more flower buds.

spring planting

By Anonymous

I just bought some blooming aster starters. How should I plant them? 2 or 3 to a cluster? Or separately? All that is on the pots is height 8", width 6", and sun.

Depending on the variety,

By Almanac Staff

Depending on the variety, plant them 1 to 3 feet apart.

Sun

By Anonymous

Will these grow towards sun (lean) in partial sun or grow straight up?

The taller aster varieties

By Almanac Staff

The taller aster varieties need to be staked so that they don't lean or fall over.

aster seeds

By Anonymous

I have started asters from seeds and am now transplanting into a larger pot. How many shoots should I have in each pot? Now there are 4-5 in each one.

Hi

By Anonymous

There should be 8-14 shoots in the pot.

asters

By Anonymous

i've left unplanted asters in original nursery plastic pots on my patio during the winter....can i salvage these??

Time to Germinate and Bloom?

By Anonymous

Anyone know the time to germination? And time to bloom?

Germination for aster seeds

By Almanac Staff

Germination for aster seeds is generally 7 to 14 days, depending on the type. Days to maturity should be on the packet--some types are 75 to 80 days. They often have a nice long bloom duration, perhaps 4 to 6 weeks if you deadhead and take care of them.

Shear off top of Asters

By Anonymous

Is it ok now in January to shear 1/3 of the top of my Asters?

Sure. You can prune your

By Almanac Staff

Sure. You can prune your asters now. They will send up new growth come spring.

aster dying off sept/oct

By Anonymous

i have asters in pots outside and in the ground they have died off now (brown and brittle leaves) if i cut them rite down will they come up again

No need to cut them down. A

By Almanac Staff

No need to cut them down. A layer of mulch will keep moisture in the soil and protect against extreme temperatures. Store the potted asters in a garage or shed. You can also dig a hole in your garden and set the pot in the hole for extra protection. Next spring you can lift the pot and put it back on your porch.

Dead head asters

By Anonymous

Can the cut flowers be left for germination or saved for Spring?

Asters can be propagated by

By Almanac Staff

Asters can be propagated by division or by planting seed in the spring. If your cut flowers had gone to seed you can save the seeds. Best time to divide an aster plant is in the spring. Cut a mature plant into 3 to 4 sections and plant each section in the garden. Asters grow quickly and will fill out in no time.

Trimming

By Anonymous

I was told to cut my aster down to the ground which I did. Do I have a problem. Also - how do tell the difference between and 8" and 8' plant? A novice!!

No worries. The asters will

By Almanac Staff

No worries. The asters will grow back.
There are many varieties of asters and some can grow to 8 feet tall when mature. If you know what variety you planted you can look it up online and see how tall it may grow.

Woods Blue Aster

By Anonymous

I live in Indiana, do I cut down my plants to the ground and mulch them for winter? The flowers are all gone....

No need to cut them down. A

By Almanac Staff

No need to cut them down. A layer of mulch will keep moisture in the soil and protect against extreme temperatures.

Potted asters

By Anonymous

I purchased asters in early October and put them in large pots with pansies. Since they are perrenials, will they come back next spring if I leave them in pots all winter on my porch. I live in central Oklahoma.

It depends on how cold it

By Almanac Staff

It depends on how cold it gets. To be safe store the pots in a garage or shed. You can also dig a hole in your garden and set the pot in the hole for extra protection. Next spring you can lift the pot and put it back on your porch.

planting

By Anonymous

I just bought an aster (not sure what type) it is october in illinois,can i put it in the ground now,or should i pot it and wait till spring? The lady i bought it from said they are hardier than mums,i planted those in late spring after potting and leaving outside all winter? however,we had a mild winter. so im just not sure. also, we have cats,so im reluctant to bring it inside. any advice?

As long as you have a

By Almanac Staff

As long as you have a perennial aster, you can plant it now. Water and add mulch after planting. If you decide to bring it indoors, try putting citrus peels in the pot to keep the cats away.
Good luck!

is OK to plant asters now??

By Anonymous

I received a small aster plant in early Sept. as a gift. Is it OK to plant that aster now-- mid-October to early Nov??

The flowers on my asters have died.

By Anonymous

Should I deadhead the dead flowers to encourage new flowers as I do my roses?

Deadheading asters

By Almanac Staff

Yes. You can pinch off the fading flowers during the growing season to encourage more blooms. Some gardeners also shear off the top 1/3 of taller asters (not dwarf types) in early summer to encourage fuller growth with more blossoms, although this can delay blooming.

flies

By Anonymous

my aster seems to attract flies...lots of flies would insecticidal soap stop them from comimg to the plant??

Give mint a try. Flies do not

By Sarah Perreault

Give mint a try. Flies do not like the smell. Either set out some pots of mint near your asters or crumble mint leaves all around the plants.
Good luck!

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