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Autumn Asters
by Judith Rogers
by Judith Rogers

I am a freelance garden writer with a weekly column ‘The Gardener’s Corner’ in the Innisfil Scope and quarterly articles in the regional magazine Footprints.

I began a blog to journal my home and garden life at Lavender Cottage. The art of afternoon tea has been a pleasure of mine for years and ‘Tea with Friends’ has become a weekly post with ladies I’ve met through blogging.

November 15, 2009

Prolong the gardening season and rejuvenate a fading flower bed with the addition of autumn asters. They’re easy, low-maintenance plants to grow and although they prefer full sun, will tolerate partial shade.

Asters don’t mind average to poor soil but located in a moist, rich soil may help reduce powdery mildew as will good air circulation between plants. Often the lower leaves of asters will wither due to dry conditions late in summer so planting something in front to conceal them is always a good idea. The purple, blue, red, white or pink daisy-like flowers combine well with black-eyed susans and goldenrod to make a stunning display.

New England (novae-angliae) and New York (novi-belgii) asters are two native species that have been hybridized to produce many of the plants found at nurseries today. These are commonly called Michaelmas daisies as they bloom around Michaelmas, an English church holiday which is celebrated on September 29.

The New England asters include many tall varieties and the popular ‘Alma Potschke’ produces a vigorous mound of large cherry-pink flowers with yellow centres. Reaching 90 cm in height, she will bloom from July right through the first frost. ‘Winston Churchill’ is a deep red New York aster that stands 45 – 60 cm tall and ‘Alert’ is a dwarf red of only 30 - 35 cm.

Michaelmas daisies can be cut back to the ground after flowering to prevent seedlings as they will not develop true to the cultivar type. Tall growing varieties can be pinched or cut back (like fall mums) to reduce mature height or eliminate the need for staking. This can be done when the plants are anywhere from 30 – 60 cm in height and will likely produce more blooms from the branching that results from the pruning. Divide these asters about every three years in the spring to remove the dead or woody centres.

A related native species is the heath aster (A. ericoides) which forms clumps of very small leaves upon which tiny white flowers bloom from August to October. This variety tolerates dry soil as witnessed growing along roadsides and is mildew resistant. The azure aster (A. azureus) is another native plant and as the name implies is a blue species and ‘Sky Blue’ that has somewhat reddish coloured stems is a tall 60 – 90 cm.

The Dumosus hybrids, often called bushy asters are an A. novi-belgii cross which have produced vigorous, disease resistant, compact plants. ‘Anneke’ is a petite 15 cm tall with dark pink flowers from September to October. ‘Jenny’ attains a 40 cm height and blooms prolifically from early September until frost with magenta flowers and yellow centres. ‘Starlight’ has wine-red flowers at 40 cm and ‘Woods Light Blue’ which is the newest dumosus introduction has light blue flowers and is mildew and rust resistant. Asters attract bees and butterflies from the nectar in the flowers. They are also the larval host plant for various crescentspot butterflies and the checkerspot.

A good source for named asters in Ontario is Lost Horizons nursery in Acton and Wildflower Farm near Coldwater sells many of the natives.

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