Garden Perennials - Asters

As gardening continues to grow in popularity more of us are looking to extend the time our gardens remain in bloom. Spring and summer are the best times for flowers but come fall most garden perennials are past their best and have already started dying back for the winter ahead. There are several late flowering shrubs that add color at this time and the changing color of the leaves of trees enhance the garden enormously. Asters are an important group of perennials which start to flower towards the end of summer and continue to produce an abundance of flowers until the first hard frost.

The leaves of Asters vary, mid green, gray-green and dark green are most common. The white, blue, purple, pink, red or purple flowers have a yellow center. They have a daisy-like appearance and develop in clusters. The Michaelmas Daisy, Aster novi-belgii, is the most widely know species but can become invasive as it self seeds quickly and roots branch outwards with even a single shoot quickly growing into a clump of Asters. However they remain an extremely popular and incredibly useful border perennial which can look incredible. Furthermore Asters make excellent cut flowers for use in flower arrangements.


Popular Asters

Garden Perennials - Asters

There are number of Aster species with each offering numerous named varieties of Asters.

A. amellus which grows up to 60cm (2ft) high and 38cm (15in) across.

A. cordifolius which grows up to 1.2m (4ft) high.

A. ericoides which grows up to 90cm (3ft) high.

A. farreri which grows up to 45cm (1.5ft) high.

Aster x frikartii which grows up to 75cm (2.5ft) high.

A. linosyris which grows up to 60cm (2ft) high.

A. novae-angiae which grows up to 1.2m (4ft) high.

A. novi-belgii which grows up to 1.2 (4ft) high.

A. thomsonii which grows up to 38cm (15in) high

A. tongolensis, syn. A. subcaeruleus, which grows up to 45cm (1.5ft) high.

Cultivation and Propagation

Plant Asters from fall to early spring in well-drained fertile soil where it will receive most sunlight. Be sure to keep the ground moist, especially during flowering. Tall plants will need to be supported but otherwise Asters are relatively easy to grow. Equally so, propagation is also easy with the best method being division while dormant. Replant separated clumps of root or single shoots, depending on how many you wish to grow, in early spring. Asters can also be grown from seed with many annual varieties of mixed colors.

Most species of Aster need to be lifted and thinned every two years with A. novi-belgii needing to be done annually. Many gardeners firmly believe that Asters should not be planted in the same ground year after year as it can lead to the problems below.

At the beginning of winter, usually after the first hard frost, the plants die back and the dead and dying leaves and stems should be cut almost level with the ground to promote good growth in the following spring.


Asters suffer from a number of diseases such as powdery mildew and yellow wilt. Powdery mildew does little harm to the plant but makes it rather unsightly as it is a fungal infection which manifests as a white powder on the leaves and stems. Yellow wilt is a far more harmful fungal disease which causes Asters to wilt and die.

Garden Perennials - Asters

If you wish to discover more about Asters and other popular garden perennials visit is dedicated to providing quality information about all aspects of landscape gardening. The author, Andrew Kelly, has been a keen gardener since his childhood and, now retired, he spends most of his spare time enjoying the hobby and writing about it.