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Asters for every garden

Excellent for massed bedding and as a cut flower, asters are easy to grow and there are both annual and perennial varieties (annual asters sown for late summer bedding are properly called callistephus).


Single, double and pompon aster flowers come in many delightful colours

Single, double and pompon aster flowers come in many delightful colours

Asters grow well in average soils, but needs full sun. Although some varieties flower in summer, Asters are best known for being a beautiful addition to an autumn flower garden. When so many other flowers end of their growing season, asters continue to thrive and provide brilliant colour and scent to an otherwise sad landscape.

The genus goes back more than 4,000 years. The name Aster comes from the Ancient Greek word astron, meaning star, which describes the shapes of the flowers. Asters are also known as Michaelmas daisies, but enthusiasts only use this name for the commonly grown Aster novi-belgii. Asters are members of the Asteraceae family. Single, double and pompon flowers come in many delightful colours — white, purple, lavender, pink or red. All asters are yellow in the centre of the flower. They are daisy-like in appearance, even though they are a member of the sunflower family. Asters come in a wide variety of sizes too, with some less than 30cm tall, while others are 60cm tall or more.

Choosing a Variety

Some common Aster species are: Aster alpinus (Alpine Aster, which flowers in summer, 15cm to 30cm tall, single flowers); Aster amellus (European Michaelmas Daisy or Italian Aster, flowers in early autumn, 60cm tall, single in clusters); Aster divaricatus (summer bloomer, 30cm to 60cm, cluster bloomer); Aster lateriflorus (Lady in Black); Aster linosyris (Goldilocks Aster); Aster pringlei; Aster scaber; Aster sibericus; Aster tataricus; and Aster tongolensis (a summer bloomer, 45cm tall, single blooms).


Asters are easily grown from division. Aster plants do best if divided every two to three years. Simply dig out half to two thirds of the plants, leaving the remainder in place. Then separate the portion you dug out into two sections and plant in another location or give them to a friend.

Aster seeds can also be directly seeded into your flower garden, or seeded indoors for transplanting later. Sow aster seeds early in the season after all frost danger has passed, and cover lightly with soil. Water thoroughly once. They germinate easily and will grow quickly. In temperate climates, if sown in autumn, the plants come into flower in early summer

Plant asters into your garden into an area where they can be grown for years. Spacing depends upon size with miniature varieties spaced four to 15cm apart, and giant varieties 30cm to 60cm apart. Place smaller varieties around the front of your flower garden as a border. Put larger varieties towards the back of the flowerbed

Asters will grow well in average soils. But, like all plants, they will reward your with bigger blooms and a healthier plant if you add plenty of compost. Also, add a general purpose fertilizer once a month.

Once your asters are established, they should grow well for years. Soil should be moist, but not wet. They will withstand dry periods. Water them during dry periods, once or twice a week to keep growth vibrant.  Add mulch around the plants for appearance and to keep weeds down.

For container-grown asters, first dig a planting hole. Then water the plant thoroughly and remove it from its container, taking care not to damage the roots. To help the plant establish quickly, carefully loosen the sides and base of the root ball, particularly if root bound, by teasing out the roots with your fingers or a hand fork. Plant asters at ground level depth so that the crown of the plant is level with the surrounding soil.

You do not need to remove dead flower blooms, except to improve plant appearance. Pinch back the tops by 15cm to 20cm at least once during the summer, to create a bushier plant and to prolong the autumn bloom. This pinching must be done prior to mid January, or it will have an opposite effect, and blooming will be reduced.

Even the smallest garden will have space for a few asters. Line out some clumps among the vegetables, moving them later into the gaps left by early flowers. Lupins, delphiniums and oriental poppies all leave plenty of space when they are over. Michaelmas daisies move easily if you soak the plants for an hour before you do the deed, and then puddle them in as you plant. Evening is the best time.

Cuttings for Indoors

Asters have sturdy stalks that make them good candidates for flower vases and other arrangements. Cut the stem low, check for insects hiding in the flower, on the stem and under the leaves. Bring them indoors and place in water immediately.

For smaller varieties, use a small container or vase and cut stem a couple inches long. Bunch up a variety of colours for an eye-appealing arrangement. Add a small sprig or two of Baby’s Breath.

Remember Asters, when creating container gardens for your deck or porch. They are excellent candidates.

Insects and Diseases

Asters are quite resistant to insects and disease. If insect or disease problems do occur, treat early with organic or chemical insect repellents and fungicide. Aphids have been known to infest Asters. Powdery mildew can also be a problem. We recommend applying insecticides, repellents, or fungicides early, before problems take hold.

It is wise to plant annual asters in a different location each season to prevent diseases, the most prominent of which is aster wilt.