Asters…in bloom until the frost arrives

Bigleaf aster (Eurybia macrophylla)
Credit: Jardin botanique de Montréal (Michel Tremblay)
Bigleaf aster (Eurybia macrophylla)
  • Bigleaf aster (Eurybia macrophylla)
  • Heart-leaved aster (Symphyotrichum cordifolium (and Solidago caesia))
  • Flat-top white aster (Doellingeria umbellata)
  • Purple-stemmed aster (Symphyotrichum puniceum)
  • New England aster (Symphyotrichum novae-angliae 'Barr's Blue')
  • Smooth aster (Symphyotrichum laeve 'Bluebird')
  • New England aster (Symphyotrichum novae-angliae 'Andenken an Paul Gerber')
  • New England aster (Symphyotrichum Blue Autumn)
Asters…in bloom until the frost arrives

As the summer season comes to an end and foliage takes on its autumn hues, asters stand out with their late, vividly colored flowering.

Asters bloom at the end of summer, and their flowering can extend over four to six weeks. They bring a touch of color late in the season and are an important source of nectar and pollen for pollinating insects, right up to when it freezes, at a time when the majority of other plants are done flowering.

Still Aster?

In light of fresh genetic information, botanical classification is constantly revised. The Aster genus has been no exception. In Québec we have over 20 native species and a few introduced species of “asters.” Now they’ve been officially spread out over a number of genera, including Symphyotrichum. But happily, the term “aster” has been retained as the common name for the species.

A burst of color in the autumn

Certain species of aster bloom as early as July. That’s the case with the heart-leaved aster (Symphyotrichum cordifolium), which features leaves in the shape of a heart, with the white panicled aster (Symphyotrichum lanceolatum) and with the large-leaved aster (Eurybia macrophylla). Undeniably these are less spectacular than others, but their interest can’t be overlooked.

Still, the most exuberant and the best-known of our planted native Québec species are probably the New England aster (Symphyotrichum novae-angliae) and the New York aster (Symphyotrichum novi-belgii). Without a doubt they’ll be easy to spot in the flowerbed come early fall.

In addition, numerous ornamental cultivars have come from these two prolifically flowering aster species.

Like a beacon

With asters, what we take at first glance to be “flowers” are in reality a capitulum, or flower head, made up of tiny flowers sometimes referred to as ‘’florets’’. The center – or disk– consists of yellow or white tubular disk florets, turning rose-colored or reddish as they age, while the surrounding white, blue or violet straplike ray florets are the flowers that catch our attention. Colorful and abundant at the end of summer, they act a bit like a beacon, attracting pollinators like bees and bumblebees, who come to collect nectar and pollen from the flowers’ shallow corolla.

Adding late-flowering species like asters to your arrangement is therefore undeniable asset when the idea is to furnish a habitat conducive to pollinators and to light up your flowerbeds late in the season.

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