Half-hardy Asters

While not true asters, half-hardy China asters come in a gorgeous array of tastefully soft colours and can be planted straight into the ground in May, says Graham Rice

- Graham Rice

ONE look at the asters on this page and we know exactly what we’re talking about, but aren’t there other flowers called asters? And what is it that makes these asters, asters?

The true asters, from a botanical point of view, are blue-flowered perennials from mainland Europe. The asters here look like them, but are annuals from China and Korea so they’re sometimes known as China asters (Callistephus chinensis). Michaelmas daisies used to be asters, too, but that’s another story.

So we’re talking about half-hardy annuals, growing from 8in-3ft (20cm90cm) in height, with single flowers or double, frilly or tightly balled, in just about every colour of the rainbow. Seed is sown indoors in spring for planting out in June, or sown outdoors in late spring. Superb for cutting, they fit into mixed borders beautifully and some make fine edging or container plants.

And yes, they come in a rainbow of colours, although perhaps not green. But one of their most valuable features is that through all these colours, the flowers have a soft look about them that is never garish or brash. So even red, white and blue combinations of asters have a soft look about them – a harmony that we never see with zinnias.

Sowing outside

These plants are half-hardy annuals, which always used to mean that we had to sow the seed about now and start them off in a propagator. Not anymore, though. As our springs have crept forward over the years, it’s become more and more clear that if we wait until mid-May we can sow asters outside where we want them to flower.

This is especially true when it comes to rows for cutting, as they can go between the rows of March-sown lettuces, and as the lettuces are cut the asters fill out into the space.