‘Colwell Galaxy’ grows to 1.2m with dazzling flowers

As yet I have no asters (symphyotrichum) in the garden. Trees and shrubs have had to come first and good asters, as opposed to the stunted specimens in small pots sold for instant display, have not been available when I have gone looking. So I will have to wait a bit longer or send off to a specialist in spring to get what I need. There is a huge variety among these plants and I am very fond of them because of the wonderful display they provide in autumn. They are loved by bees and butterflies too.

Symphyotrichum oolentangiensis is a Canadian species with lilac flowers

They are not perfect though. Most need regular division, especially the Novi-belgii types which are very prone to mildew. They are best, and least prone to mildew, if they are divided and replanted every two years or every year, in spring, and that means you need easily-worked soil which does not describe the sticky lumps I have at the moment. Most are also rather dull for most of summer while they build up energy for their autumn displays. But they are so spectacular in autumn that they can be forgiven for this.

Years ago when I grew a lot, plants such as the old ‘Climax’ would barely reach 1m high with masses of thin stems if neglected, leaves ragged with mildew. But when divided and replanted as single shoots stems would top 1.5m and be healthy and covered in bloom.

The late-flowering types, which are roughly divided into the Novi-belgii types and the Novae-angliae, have flowers in a wide range of colours, though there are also other species, equally charming, which tend to have smaller flowers and a more delicate appearance. All are derived from North American native species.

Trawling through my photo library, for plants other than asters, I found these and thought they deserved an airing, just because they are so colourful – necessary after yesterday’s dull photos of mud.

‘Miss K E Marsh’ grows to 90cm with lilac pink blooms

Just by chance, all are of Novae-angliae asters. These rarely get mildew and the leaves are usually covered in rough hairs, unlike their cousins. However, I do not like them as much as the Novi-belgii types because they tend to be more upright, with no branching except at the top of the stems and they hold their blooms on rather congested clusters rather than airy sprays. The Chelsea chop will sort their habit problems.

‘Andenken An Alma Potschke’ reaches 1.5m and is the best known, but the flower colour is rather harsh to my eyes

aster ‘Andenken An Alma Potschke’, aster ‘Colwell Galaxy’, aster ‘Miss K E Marsh’, how to grow symphyotrichum, Symphyotrichum oolentangiensis