Aster

( ASS - ter )

At-A-Glance Information

These popular perennial flowering plants need full sun and regular water for best performance in the landscape. Their bright blooms will attract butterflies and other pollinators to the garden. Species range in size, flower color, foliage, and habit. Blooms can come in blue, red, pink, lavender, or purple, and mostly have yellow centers, flowering in late summer into fall. Asters have a spreading habit, and will grow rapidly via rhizome roots in optimal growing conditions. Plant Asters in containers or potted arrangements or in mixed beds and borders. Taller varieties do well when surrounded by lower-growing plants, which will hold up their stems and hide their sparse basal foliage.

ASter Species and Varietals

The genus Aster is a member of the plant family Asteraceae, and includes somewhere around 170 species. Aster growing zones vary by species; for more information, see the descriptions below. To find your zone, click here: Zone Map.

Aster alpinus (Alpine Aster, Blue Alpine Daisy)
This species is native to European mountain ranges and has pink, purple, or blue flowers that bloom in summertime. These plants prefer a soil pH of between 6.0 and 7.5. Plants generally reach up to 6-12 inches tall with a spread of 6-15 inches. Alpine Aster grows well in USDA hardiness zones 3-9.

Aster amellus (Italian Aster, European Michealmas Daisy, Italian Starwort)
This species grows best in USDA hardiness zones 4-8 or Sunset growing zones 2-24 and is native to Europe and western Asia. This plant is sturdy, to 2 feet tall and 1.5 feet wide. Flowers are violet with yellow centers, about 2 inches across. This species loves alkaline soils.

Aster bellidiastrum (False Aster, Daisy Star Aster, Alpine Aster, Mountain Daisy, Astro Falsa Pratolina)
This species produces white daisy-form flowers and is considered to be a wildflower. These plants form a basal rosette of green foliage and tall, thin stems. False Asters grow well in USDA hardiness zones 3-8, and typically reach up to 8-12 inches tall when mature and in bloom. This species is considered invasive in some areas, particularly the western United States.

Aster dumosus (Symphyotrictum dumosum) (Bushy Aster, Rice Button Aster, Long-Stalked Aster, Bushy American Aster)
Native to the eastern United States, this species grows best in USDA hardiness zones 3-8 or Sunset growing zones 1-24 and is a compact, dense plant. Lilac blooms appear in large numbers in summer and fall. Great for pots. 'Sapphire' is a choice garden ornamental cultivar.

Aster x frikartii (Frikart's Aster, Michaelmas Daisy)
Best in USDA hardiness zones 5-9 or Sunset growing zones 2b-24. This hybrid is one of the most widely adapted species of Aster. Plants form a loose mound 2 feet tall and wide, with dark green leaves and sprays of lavender to violet-blue single flowers that are excellent for cutting. Blooms from summer to fall in most areas, though will bloom year-round in places with mild climates if flowers are dead-headed regularly. This species attracts bees. Varieties include 'Monch' and 'Wunder con Stafa' ('Wonder of Staffa').

Aster laevis (Smooth Aster, Smooth Blue Aster, Smooth-Leaved Aster, Glaucous Michaelmas, Glaucous Aster)
Grows best in USDA hardiness zones 3-8 or Sunset growing zones 1-10 and 14-21, and is native to central and eastern North America. Plants reach up to 3.5 feet tall and 1.5 feet wide, and have smooth foliage that is mildew-resistant. Clusters of deep purple-blue flowers bloom in autumn.

Aster lateriflorus (Symphyotrichum lateriflorum) (Calico Aster, Side-Flowering Aster, Starved Aster, White Woodland Aster)
These Asters grow best in USDA hardiness zones 4-8 or Sunset growing zones 1-10 and 14-21 and are native to North America. To 4 feet tall and 1 foot wide. Flowers are purple-pink, and the branching habit is arching and profuse. In early fall, foliage will turn a coppery purple-red color. Needs partial shade. Varieties include 'Lady in Black' and 'Prince', both of which have black-purple stems and leaves and white blooms with red centers. This species can spread aggressively, but is not considered invasive.

Aster maackii (Maack's Aster, Maack's Starwort, Maack's Michaelmas Daisy)
Named for Russian naturalist Richard Maack, this species was first described in 1861 by Eduard August von Regel. These plants produce light purple daisy flowers, and reach up to 1.3 and 3 feet tall when mature with a spread of 1 to 1.5 feet wide. This species grows well in USDA hardiness zones 4a-8b.

Aster novae-angliae (New England Aster)
This species is best in USDA hardiness zones 3-8 or Sunset growing zones 1-24 and is native to an area that ranges from Vermont to Alabama, west to North Dakota, Wyoming and New Mexico. Individual plants grow to reach 3-5 feet tall and as wide at maturity and have violet-blue flowers, though some varieties of the species have flowers in blue, white, pink, reddish, or deep purple. These plants are tolerant of wet soils, where they will freely reseed, and enjoy full sun to partial shade. Varieties are outlined below:

'Alma Potschke'
Salmon-colored single-blooms on 2-4 foot tall stems flower from late summer to early fall.

'Harrington's Pink'
Clear pink single-flowers bloom on 3-4 foot tall stems over the fall season.

'Purple Dome'
Mildew-resistant variety with bright purple flowers. Compact grower (1.5 feet tall).

Aster novi-belgii (New York Aster, Michaelmas Daisy, Sapphire Aster)
Grows best in USDA hardiness zones 3-9 or Sunset growing zones 1-24 and is a native to eastern North America. Gets to 4 feet tall and 3 feet wide. Blue-violet clusters of flowers contrast with smooth green leaves. Many different varieties are available for purchase, with flower colors that range from white, cream, and blue to lavender, purple, rose and pink. This species is considered invasive in Europe. Varietals are outlined below.

'Alert'
Has ruby red, semi-double flowers. 1 foot tall, 1.5 feet wide.

'Jenny'
Double, purple-red flowers.
1 foot tall, 1.5 feet wide.

'Little Pink Beauty'
Soft pink, semidouble flowers. 1 foot tall, 1.5 feet wide.

'Prof. Anton Kipppenberg'
Lavender-blue, semidouble flowers. 1 foot tall, 1.5 feet wide.

'Snowsprite'
White flowers open from pink buds, 1 foot tall, 1.5 feet wide.

'Audrey'
14 inches tall and a little wider. Lavender-blue flowers.

'Farmington' ('Baldco')
1.5 feet tall and 2 feet wide, mildew-resistant with lilac flowers.

'Patricia Ballard'
2.5-3 feet tall and 2 feet wide with dark pink flowers.

'Apple Blossom'
Pink flowers, grows to about 3 feet tall and wide.

'Marie Ballard'
Pale blue, double flowers, gets to 3 feet tall.

'Winston S. Churchill'
Dark red flowers that are semi-double. The plant gets to around 3 feet tall and wide.

'Climax'
Large sprays of medium-blue blossoms on 6-foot tall stems.

Aster tataricus (Tartarian Aster, Tatarinow's Aster)
This species is commonly used as an edible plant in Korean cuisine, and produces lavender to bluish flowers. It forms an erect, tall plant that can reach up to 6 feet when mature and in bloom. Flowers are small but abundant, and bloom in fall. Cultivar 'Jindai' is a bit shorter than the straight species, only reaching between 3 and 4 feet tall. Native to Siberia, China, Mongolia, Korea, and Japan and does well in USDA hardiness zones 3-9. This species is considered an invasive plant in parts of North America.

Aster yomena (Kalimeris yomena) (Kalimeris, Japanese Aster)
This native of Korea and Japan is used by locals to flavor dishes, and is considered an easy-care plant commonly grown in gardens. Japanese Aster grows well in USDA hardiness zones 5-8. Cultivar 'Shogun' has variegated foliage and is a popular garden ornamental.

Caring for Aster

Asters are commonly grown from seed, but can also be purchased as specimens from a reputable nursery. Grow Aster plants in a spot in the garden that receives full sun exposure; between 6 and 8 hours of direct sun each day will result in the best foliage, growth, and blooms. Asters will adapt to most soil types, but growth is best in fertile soil amended with organic matter. For best growth and bloom, amend soil around the plant site before setting the plant in with plenty of compost and/or other organic material. They do well with a soil pH of between 5.8 and 6.8 (acidic to neutral). Apply a layer of mulch around the planting area to suppress weed growth, maintain consistent soil temperatures, and to increase soil moisture retention. Water new plantings regularly as they form a strong root system. At maturity, Asters are appreciative of consistently moist soils, which will result in the best shows of flowers. As a general rule of thumb, water whenever the top inch of soil feels dry to the touch.

Feed with a dressing of organic compost each year in early springtime, adding some to the area before planting and working it into the soil. Taller cultivars can be cut back to encourage bushier growth; some may need to be staked in order to remain upright, especially in areas with high winds. Divide plants yearly in late fall or early spring, tossing the inner growth in the compost bin and replanting the newer, younger outer portions. Less vigorous Asters can be divided once every two years. For instructions on how to successfully divide Aster plants, see the Propagation section below. Asters are perennial plants, able to last up to around 10 years in the landscape before needing to be replaced.

Growing Aster In Containers
Asters grow wonderfully in the ground, but can also be cultivated in containers on patios or walkways. Choose a pot with adequate drainage holes on the bottom to allow excess water to flow away from the root zone. Use a well-draining potting mix amended with organic material and perlite. Apply a layer of mulch on top to suppress weed growth, maintain consistent soil temperatures, and to increase soil moisture retention. Water new plantings regularly as they form a strong root system. At maturity, Asters are appreciative of consistently moist soils, which will result in the best shows of flowers. As a general rule of thumb, water whenever the top inch of soil feels dry to the touch. Prune to remove dead, damaged, or diseased foliage at any time during the growing season, and deadhead spent flowers to encourage more blooms to form. Divide plants when they begin to perform poorly, which happens about every two years when Asters are grown in containers. For instructions on how to successfully divide Aster plants, see the Propagation section below.

Harvesting Aster
Aster flowers are cultivated for their cut flowers as well as their edible parts. Asters grown as cut flowers are harvested in late summer to fall, and are cut-and-come-again flowers, meaning harvested stems will be replaced with more blooms. The best time of the day to harvest Asters for bouquets or arrangements is in the morning, after dew has dried but before the heat of the day sets in. Cut flowers at the base of their stem at an angle using sharp, clean shears. Drop them into a bucket of cool water until they are ready to be used. When arranging, remove all leaves below the water line. Asters generally last for between 5 and 14 days. To maximize vase life, re-cut the base of stems and refresh water every few days.

In addition to their ornamental value, Aster roots, foliage and flowers are edible. Roots are not widely consumed. Flowers and leaves can be eaten dried or fresh, added to salads or cooked lightly for use in soups. Flowers also make a great garnish for fruit salads, green salads, desserts, and mixed drinks. They can also be steeped in a tea alongside other herbs. Harvest flowers in the morning after dew has dried, cutting the stem about 4 inches above its base. Hang the stems upside-down in a cool, dark area until it dries completely. Flowers can then be harvested and stored in an airtight container in a cool, dark, dry place for a year. Discard after one year.

Disclaimer: Information contained on this website is strictly and categorically intended as a reference to be used in conjunction with experts in your area. Foraging and consumption of plant parts should never begin without the guidance and approval of a local plant specialist. The providers of this website accept no liability for the use or misuse of information contained in this website.

Propagation

The most straightforward way to propagate Asters is through division of existing plants. This process will need to be completed every year to every few years (depending on the species and cultivar grown) to ensure the best health for plants. Asters can also be propagated via seed, though this method can result in offspring that do not have the exact same qualities as the parent plant. To propagate your Aster plant, follow the instructions below.

Propagating Aster by Division
This type of propagation is relatively simple; you will need a clean shovel, mulch, fresh soil, compost, and pots (only necessary if you will be saving divided plants for transporting elsewhere). Division is best done in spring or fall (after the plant has entered dormancy and been cut to the ground, but before it has begun its new spring growth), and needs to be done every four to five years regardless of whether you have the goal of propagating the plants for best performance. To propagate by division, follow these steps:

Gather your materials. Using a shovel, dig up your existing plant. Start from the outside and work your way in to avoid damaging the roots. Once you have worked it up out of the ground, lay it out.
Start to tease apart the roots. Once the roots are untangled, separate your plant into segments, ensuring that each one has at least one thick root section. Remove any dead roots at this time.
Prepare your pot(s) or new planting site(s) with amended, well-draining soil. You can either bring in new soil or simply amend your existing soil with compost to complete this task. Then, plant your divisions and water thoroughly.
Apply a thick layer of mulch over the new planting to protect it from cold weather as it acclimates to its new home.

Propagating Aster by Seed

Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. The best potting medium for seed germination is a light blend of 1/3 pasteurized soil or compost, 1/3 sand, vermiculite or perlite, and 1/3 coconut coir or peat moss.
Harvest your seeds. The seed heads on Aster plants are left behind after flowers have faded. Once they have dried out, you can harvest the seeds. Cut the flowering heads off of the plant, placing them in a paper bag. Harvest as many as you can, and place the paper bag in a dry, cool, dark area. They will begin to release the seeds contained inside. Once they have been released, take them out of the bag and put them in a container to work with them.
Water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a quarter inch to a half-inch under the soil surface. Cover them with soil and water with your spray bottle. Place your tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes 7-14 days from sowing. Once you begin to see seedlings sprout and they are able to be handled, transplant them to their own individual 3-inch pots, filled with the same potting medium as described in Step 1. Loosen the seedlings from the potting medium by digging down with the tines of your fork about an inch and a half, gently working the seedling up until it is out. Then, replant the seedling in its individual pot.
Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.