Home of the Practically Perfect Pink Phlox and other native plants for pollinators

Wednesday, October 24, 2018

Wildflower Wednesday: Frost Aster's moment in the sun

The blue wood ex-asters have always over shadowed the Frost asters in my garden until this year!
That's when I noticed how delightful it looked arching over the Susans and other spent blooms in the sunniest garden beds. It's a blizzard of small bright white flowers and on sunny autumn days it's busy hosting bees of every size and any butterflies still out and about. Frost aster is doing the job I had hoped the Boltonias would do: blooming late and attracting pollinators. And it's doing it in dry soil.

Symphyotrichum pilosum is known by several common names, depending upon what part of its growing range you hail from: hairy aster, frost aster, hairy white aster, old-field aster, and, awl aster.

Often described as a bushy plant, it's a delicate arching plant at Clay and Limestone.  Snipping it back early in the summer might make for a shorter and bushier plant, but, I prefer the graceful look of arches in my garden to counteract the many tall wildflowers.

Frost aster started blooming as the S novae-angliae and Solidagoes were beginning to decline and just as the little asters everywhere began to bloom. They're still blooming and looking good after several heavy rainfalls and two frosty nights. I appreciate its long lasting floral display and so do the pollinators. Late blooming flowering plants are extremely important food sources for pollinators still out and about on beautiful warm fall days.

During the summer the green stems are hidden by Susans and other blooming beauties. You might consider combining them with bluestems (the red fall colors would be a delightful contrast) or perennials like Tradescantia and Phlox paniculatas.  If your garden is dry, Monarda punctata, Parthenium integrifolium and Asclepias tuberosa gone to seed would be good partners.

yellow centers are surrounded by many (16-35) white ray florets
Frost Aster has a lot going for it:
  • an easy peasy, no maintenance plant
  • a delightful extended season of bloom (Sept - Dec), 
  • showy white flowers
  • graceful arching stems
  • a floral display that keeps on keeping on~it's not stopped by rain, sleet, snow or freezing
  • a delicate sweet scent
  • a pollinator magnet 
the stems of this little aster are covered in fine, fuzz-like hairs
Frost aster is a Clay and Limestone rough and tumble wildflower.  It's a simple flower that blooms its heart out and require no special care. Please note, like many members of the Asteracea family, this one is a traveler (self seeding), but you can easily transplant any seedlings to other parts of your garden. If you don't want to edit, cut the flower heads off after bloom, but, remember,  you will be depriving song birds and small mammals of those seeds.

Symphyotrichum pilosum is native to every state in North America east of the Rockies and also to eastern Canadian provinces. In Latin, pilos means 'hairy' and the stems of this little aster are covered in fine, fuzz-like hairs.
 Symphyotrichum is a genus of about 90 species of herbaceous annual and perennial plants that were formerly treated within the genus Aster; I affectionately refer to them as the Ex-asters. Frost aster like the other ex-asters in my garden is native to Middle Tennessee. They all grow and thrive in the shallow clay soil and semi-shady to almost full sun conditions of my Zone7 garden (formerly Zone6b)
the yellow centers may become reddish with age
The Particulars

Botanical name: Symphyotrichum pilosum
Common Name: hairy aster, frost aster,  hairy white old-field aster, awl aster
Type: Herbaceous perennial
Family: Asteraceae
Native Range: Eastern North America and western Canada
Zone: 4 to 8
Height: 2.00 to 4.00 feet
Spread: 2.00 to 4.00 feet
Bloom Time: September to October and into November (middle Tennessee)
Bloom Description: White rays and pale yellow center discs. Showy and attractive to native bees and butterflies
Leaves: Alternate, Simple, Entire; Long lance-shaped. The lower ones often disappear during hot summer months
Sun: Full sun to part shade
Water: Mesic to dry conditions
Soil: Loam, clay-loam, sandy loam, or gravelly material
Maintenance: Low
Distinctive features: Very fuzzy stem, as if coated with a thick frost.
Comments: This aster is easy to cultivate, but it can spread aggressively by reseeding itself, especially in open disturbed areas. You'll see this plant out the car window in empty field, highway  medians,  disturbed areas, along railroad tracts and empty neighborhood lots.
Wildlife Value: Moderately deer resistant. Host plant for the Pearl Crescent butterfly. Flowers are attractive to bees and butterflies. Songbirds and small mammals eat the seeds. Members of the genus Symphyotrichum species support the following specialized bees: Andrena (Callandrena s.l.) asteris, Andrena (Callandrena s.l.) asteroides, Andrena (Cnemidandrena) hirticincta, Andrena (Cnemidandrena) nubecula, Andrena (Callandrena s.l.) placata, Andrena (Callandrena s.l.) simplex, and Colletes simulans.  (source)
Ecological Value: Because of its "weedy" nature it is great at colonizing disturbed and "waste places". It protects soil from erosion and provides food for wildlife where more sensitive plants cannot yet grow.(source)


*The Bumble Bees, honeybees, Miner bees, and large Leaf-Cutting bees (long-tongued bees), bee flies, butterflies, and skippers that visit all the late blooming ex-asters for nectar and pollen are essential for cross pollination or all those fluffy seeds would be infertile. So never, ever, ever, ever use pesticides, if you want pollinators to pollinate your ex-asters and other plants!

Welcome to Clay and Limestone and Wildflower Wednesday.  This day is about sharing wildflowers and other native plants no matter where one gardens~the UK, tropical Florida, Europe, Australia, Africa, South America, India or the coldest reaches of Canada. It doesn't matter if we sometimes share the same plants. It doesn't matter if they're in bloom (think winter sharing), how they grow and thrive in your garden is what matters most.

Gail Eichelberger is a gardener and therapist in Middle Tennessee. She loves wildflowers and native plants and thoroughly enjoys writing about the ones she grows at Clay and Limestone. She reminds all that the words and images are the property of the author and cannot be used without written permission.


  1. I love asters and yours are beautiful! Ours have been done blooming for awhile. I'm not sure if we have frost asters on our property or not...there are some that look very similar but I'm pretty sure they are panicled aster. But then I have a hard time getting all the species right so who knows?
    I found your blog by accident a few weeks back and decided to join you for Wildflower Wednesday. Thank you for hosting it!

    1. So cool! Glad to have you here. xo

    2. Hi Joanna, your wildflower is one that is new to me. What a beauty! I didn't leave a comment on your blog because I didn't want to leave my email address there.

  2. I always enjoy your posts, Gail! I still call them asters, and cannot tell them apart. I have several kinds here in SE Nebraska, some of which are cultivars. I don't think I have this kind, but I do have some that are white. They may be heath asters. I see my link did make it on the post. I didn't think it had.

    1. I have to research them all to tell some apart. I call them the ex-asters, it's easier and a lot of fun.

  3. I do believe I have some frost asters in my front garden & you make a very good point about the importance of late flowering plants as there really is not that much around at this time of year - you're always such a font of knowledge :)

    1. They're so cute, I am thrilled to have begun to notice how lovely they are instead of thinking the lilacs and blues are prettier! Thanks for the compliment; I do research a bunch before posting. xo

  4. There is something about the asters with the tiny white blooms that I adore!

    1. I do, too. I love seeing the star that's left behind after the seeds are dispersed, too.

  5. Since it's almost Halloween, I decided to write about the creepiest native plant I know of!

  6. I wonder if this is what popped up in my garden. I have left it where ever they want to grow. They seem so light and airy, so delicate looking yet we know they are tough as nails.

    1. That's one of the identifying behaviors of Frost aster, it just appears without being planted...a gift from a bird or the wind!

  7. Thanks for your posts. They bring a few moments of quiet sanity.

  8. I have something similar in my western NY garden, but I have generally pulled them out as "weeds". Since I'm having some much deer destruction, I think I'll leave them next year and see what happens. I know your summary says moderately deer resistant, but at this point, I'm desperate and on the verge of reducing the gardens because wildlife (rabbits, chipmunks, squirrels and moles beside the deer). Thanks for your posts, I'm learning a lot.

    1. The critters can be so frustrating. I've lost many plants to them and my heart goes out to you and all gardeners who have herds of deer ruining their gardens. Last winter the voles decimated my spring ephemerals. I was heartbroken when there were no trout lilies and very few trilliums. I hope you can find a balance. xo

  9. Gail, I think I have it in my woods. If so, it delicately arches here too. So many ex asters. I love them all.~~Dee

    1. They're the best and since you're on the Monarch trail they would love any and all you have for nectar on their long flight. The bees need the pollen and nectar to fortify their nests for winter. It's a win-win for us and them.

  10. You make a very strong case for this aster. If only I had more sunny spaces in our garden.

    1. It also planted itself in a container, so you could try that!


"Insects are the little things that run the world." Dr. E O Wilson