Aster

Asters are the stars of the autumn border, providing an array of cool-coloured flowers from September to Christmas.

Recommended varieties

Asters have been in the UK for more than 400 years, but the genus goes back more than 4,000 years.

Aster novae-angliae

The name 'aster' comes from the Greek word for star. 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. This family has composite flower-heads, with the central disc composed of up to 300 individual flowers, usually yellow or orange. This is surrounded by large, brightly-coloured petals, designed to attract pollinating insects.

Annual asters sown for late summer bedding are properly called callistephus.

A. x frikartii 'Monch'
A. amellus 'Rudolf Goethe'
A. amellus 'King George'
A. ericoides
A. turbinellus

Growing tips

Most perennial asters flower in late summer and autumn. To get the best effect, plant them at the back of a border combined with other late-flowering plants, such as Japanese anemones.

Asters are fast-growing perennials that will benefit from being divided in late autumn or early spring every year or two.

Divide the clumps with a spade, discarding the old dormant sections from the centre. Replant the vigorous growing outer portions into newly prepared ground. The taller growing varieties benefit from staking to prevent them from being damaged by strong winds.

Watch Sarah Raven's guide to dividing asters:

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Problem solver

Many perennial asters, especially A. novi-belgii , have a tendency to succumb to mildew.

To prevent this, keep plants well watered and apply a mulch around the base of the clump to retain moisture at the roots. Spray with a suitable fungicide at the first sign of disease.