Skip to content
Growing asters from seed

Endless Summer: Growing Asters from Seed

Think of your ornamental garden like a fireworks show, beginning in early spring. Once you've set up your folding chairs and cracked open that cold beer, the anticipation sets in. Your early blooming flowers begin bursting with color, and the pyrotechnics start to ramp up with vivid displays of color, exciting patterns and shapes and surprising, out-of-the-blue high notes.

Just when you begin to think you've seen it all, and that the show's winding down, KAPOW! The grand finale!

The gardener's equivalent to a fireworks crescendo is the spectacular end-of-summer encore performance starring flowers in the Asteraceae family. If you want your garden to go out with a bang this fall, you'll definitely want to plant a ton of asters.

Aster's Origins and (Befuddling) Nomenclature

Until genetic research in the 1990s, North American and Eurasian asters were thought to be all but the same. Now, for the most part (as in, expect a ton of contradictions) they're split into separate genera; Old World asters are usually assigned the genus "Aster," while about a dozen genera classify New World species. Of course, then you have China asters (Callistephus chinensis) which are native to North Korea and China. All fall within the Asteraceae family.

Many New World asters are still classified in catalogs and botanical gardens by the genus Aster, though they've technically been reclassified under another name. For example, the popular New England asters are now Symphyotrichum novae-angliae, but if they're not listed by their "old" name Aster novae-angliae, gardeners might begin eating dirt, shaking their fists at the sky, and running around with their garden clogs on the wrong feet, because:

  1. Who can remember Symphyotrichum?
  2. Who can even spell it?
  3. Change = BAD
  4. They're still asters, dammit!

Flowers in the Asteraceae family are native to regions all over the globe, with the exception of Antarctica and the Arctic. Those that are considered asters (New World or Old) are listed, in alphabetical order, by these genera:

  • Almutaster
  • Aster (duh)
  • Callistephus
  • Canadanthus
  • Doellingeria
  • Eucephalus
  • Eurybia
  • Ionactis
  • Oligoneuron
  • Oreostemma
  • Sericocarpus
  • Symphyotrichum

  • The only "true" aster that's native to North America is Aster alpinus, but many Old World varieties have hitched a ride and made themselves at home on this continent.

    The name "Aster" is derived from the Greek word for "star." Callistephus, the genus for China asters, means "beautiful" (kalli) "crown" (stephos).

    While asters aren't exactly star-shaped, their long, narrow petals do radiate outward from a round, yellow center. Sunflowers are also a member of the Asteraceae, and if the sun is really a star, then the botanists who named asters were onto something...though perhaps in a roundabout kinda way.

    Cultural Significance

    We humans tend to associate pretty much anything to...well, pretty much anything. Flowers are no exception; in our long history as a species, we've used flowers to express ourselves in both love and war:

    • French soldiers honor fallen comrades by adorning their graves with asters.
    • The aster is a popular decoration for the Festival of St. Michaelmas, and some aster varieties are referred to as "Michaelmas daisies."
    • Asters are the symbolic flower for those born in September.
    • Red and blue asters represent new beginnings and are considered good luck for students and newlyweds. (More on red asters in a few.)
    • Dissidents in the Hungarian Aster Revolution wore the flowers during their October 30, 1918 protests in Budapest.

    Nobody knows the sentimental value of flowers better than the famous floral delivery company, FTD. If we were lazy (and really, we aren't) we'd just cut-and-paste their entire aster page.

    Instead, we'll cover the highlights as they relate to mushy Hallmark holidays, making up after lovers' quarrels, and embarrassing spouses with arrangements delivered to workplaces:

    Asters symbolize love, wisdom, and faith. If you're looking to woo someone, send them red and pink asters, which represent undying love, sensitivity, and devotion. White asters represent innocence and purity, making them a great choice for new babies, or for driving home a particular point when celebrating your teenager's Sweet Sixteen, quinceanera, confirmation, or Bar/Bat Mitzvah.

    Purple asters represent royalty and wisdom, so send them to your mom or your in-laws if you really want to be a suck-up.

    Asters in Herbal Medicine

    We were surprised to learn that these pretty ornamentals have a long history as a medicinal plant, though they seem to have become neglected by western herbalists in the last century.

    According to herbalist Jim McDonald, Native Americans, particularly those culture in the Northeast and Plains regions, extensively used New World asters. They burned asters to create a cleansing smoke in sweat lodges, and used the flowers and roots of the plant for the following:

    • Revive the unconscious
    • Treat mental illness
    • Staunch nosebleeds
    • Ease headaches
    • Relieve congestion
    • Relieve gas pains and stomach aches
    • Treat earaches
    • Reduce fevers

    McDonald's research into the medicinal uses of asters is focused upon New England asters, and we highly recommend you check out his page for a deep-dive into how the plant may play a role in modern herbalism.

    We did some digging on asters in Eastern traditional medicine and learned that the Chinese used asters for many of the above, as well as for epilepsy, circulatory issues, and (yay!) hangovers. Asters are most commonly used in Asian medicine for respiratory issues.

    Asters in the Garden

    It's tough to get down to the fine details of plant cultivation when there is such an expansive selection among Old World and New World asters. We're going to break things down into two popular types: The annual China asters and the perennial New England asters. Most of the other species fall somewhere in between, so we always recommend verifying growing habits and cultivation requirements on the backs of your seed packets.

    China Asters (Callistephus chinensis)

    China asters are perhaps the most widely-cultivated flower among those recognized as asters. With a wide environmental tolerance, numerous shades and textures, and exceptional height, C. chinensis is a stunner as a backdrop plant.

    Type: Annual

    Plant Height: 2-3'

    Plant Width: 1-1.5’

    Bloom Period: July through September

    USDA Growing Zones: 2-11

    Water Requirements: Moderate. While most asters can tolerate drought due to their deep taproots, it's best to keep them evenly moist.

    Sunlight Requirements: Asters prefer full sun, but can tolerate partial shade.

    Soil Requirements: Rich, well-drained soil. Amend compacted or clay-like soil with plenty of mature compost to improve drainage.

    pH: ‎The ideal range for China asters is 5.5-7.5.

    Foliage: Medium-to-dark green leaves are lance-shaped with broadly-spaced serrations.

    Pests and Diseases: Watch out for aphids and mildew. Otherwise, China asters are hardy and not particularly susceptible to garden cooties.

    New England Asters (Symphyotrichum novae-angliae)

    New England asters tower over most other varieties, and if purple means "regal" in the language of flowers, this one is the king of the fall garden. Dark pink, indigo, or purple single-layered flowers, about an inch-and-a-half in diameter, resemble their daisy cousins; raised, yellow centers offset the colors of the petals, and the abundant blooms nearly hide the dark, hairy, lance-like leaves.

    Some New England asters might require staking in windy areas, though their stems are fairly durable and, at their bases, somewhat woody.

    Type: Perennial

    Plant Height: 3-6'

    Plant Width: 2-3'

    Bloom Period: August through September...or whenever your first frost lowers the curtain on the growing season.

    USDA Growing Zones: 4-8

    Water Requirements: Moderate. While most asters can tolerate drought due to their deep taproots, it's best to keep them evenly moist. We recommend using ground-level watering, such as drip irrigation or soaker hoses.

    Sunlight Requirements: New England asters prefer full sun, and are less shade-tolerant than most other varieties.

    Soil Requirements: New England asters can tolerate clay soils, but it prefers a rich, well-drained soil. Amend compacted beds with plenty of mature compost to improve drainage.

    pH: 5.1 to 6.8, preferring the more acidic end of the spectrum.

    Fertilization: Asters benefit from a general-purpose liquid fertilizer shortly before flowering begins, and halfway through the bloom period.

    Maintenance: Pinch the tops of your plants to delay blooming, and to keep them in a more compact shape. Once they've died back in spring, remove the entire plant (annual China asters) or trim them back to ground level (perennial New England asters). You'll want to divide the roots every 2-3 years to keep your long-lived New England asters healthy and growing strong.

    Pests and Diseases: Aphids and mildew are the most common issues associated with New England asters.

    Where to Plant Your Asters

    • Asters are best used as backdrops: Along a sunny fence or wall, in the far corners of a garden.
    • Grow your asters near taller sunflower varieties to maintain a sense of scale; the purple New England asters look stunning near bright yellow, red, or orange flowers.
    • Asters pair well with the cup-shaped flowers and fern-like foliage of cosmos.
    • Another late-blooming plant, cleome, works well near China asters.
    • Coneflower (Echinacea) are also late-bloomers and look great with asters.
    • Anywhere you want to enjoy a riot of butterflies and pollinators!
    • In a vase! Asters are excellent cut flowers.

    Growing Asters from Seed

    Once you get them started and the weather warms up, asters are rapid growers! Follow these guidelines to grow your own New England or China asters from seed.

    Indoors/Outdoors: We recommend starting your China asters indoors (2-3 seeds pressed into moist peat pots, started 4-6 weeks before your last frost) for best results, though you can direct-sow them in fall or, after the soil temperatures have warmed up to at least 70°F, in the spring. New England asters should be direct-sown; broadcast them on fine, moist soil.

    Whether you start your seeds indoors or out, water them with a fine mist to prevent them from becoming "buried" under the soil.

    Plant Depth: No more than 1/16" deep; asters need sunlight to germinate.

    Plant Spacing: Give these babies plenty of room; we recommend 24" for China asters, and 36" for New England asters. If you broadcast seed your asters, be sure to thin them as they grow.

    Germination Time: 7-14 days

    Transplantation Time: Harden off your indoor starts, and plant them when the daytime soil temperatures are consistently above 70°F. China asters, in particular, aren't frost-tolerant.

    We're Your Pyrotechnic Specialists

    You might not want us in charge of explosives—that would be messy—but if you want a spectacular high-flying, late-season display of all your favorite colors, check out our aster seed collections, or contact us at Seed Needs. We offer the most popular and reliable varieties to keep your garden blooming well into fall.

    Who knew you'd be looking forward to the end of summer?

    Older Post
    Newer Post