Symphyotrichum
The largest group of plants moved from Aster, about 90 species, almost all from America. It contains the widely grown Michaelmas daisies, S. novi-belgii, (New York asters) and S. novae-angliae, (New England asters). From our experience these have smoother leaves, smaller flowers, than Aster. Many excellent cultivated forms available, with a rainbow of colours and some with lovely contrasting dark stems. Good for late colour in the herbaceous border, generally in full sun.
Irrespective of the vagaries of taxonomy, all species of Aster, past and present, are of immense value to pollinating insects, especially butterflies, bumblebees, honeybees and hoverflies, particularly in the late summer to autumn garden. The North American species (now called Symphyotrichum spp.) can be invasive in grassland or wetland habitats and so care should be taken not to let them outside of the confines of the garden.