- Name also: European Michaelmas Daisy, Italian Aster
- Family: Daisy Family – Compositae, subfamily Asteroideae
(formerly Aster Family – Asteraceae)
- Growing form: Perennial herb. With subterraneous runners, forms stands.
- Height: 40–70 cm (15–30 in.).
- Flower: Flowers form 2.5–7.5 cm (1–3 in.) wide, single flower-like capitula surrounded by involucral bracts. Capitulum’s ray-florets white, blue or red, tongue-like; disk florets yellow, tubular, small. Stamens 5. Gynoecium composed of 2 fused carpels. Involucral bracts in several rows. Capitula in groups of 5–15.
- Leaves: Alternate, lower leaves stalked, upper stalkless. Blade lanceolate–narrowly obovate, often with toothed margin.
- Fruit: Achene with quite long, unbranched hairs on tip.
- Habitat: Ornamental.
- Flowering time: August–September.
Aster means star in Latin and Greek, and asters used to be colloquially known as starflowers. This large genus includes around 250 species, of which at least 100 are grown as ornamental plants. These perennials are relatively new arrivals, only becoming popular additions to Finnish gardens at the beginning of the 20th century, but they have become hugely popular since then, and asters are nowadays familiar plants in nearly every Finnish garden. Michaelmas daisy thrives in sunny parts in gardens with rich soils and good drainage. Most asters are native to North and Central America, but Michaelmas daisy is an original European species. Not all the species of aster that are cultivated in central Europe can be grown in Finland, but several thrive so well that they grow far beyond the pale of the flowerbed. Able to thrive and spread without help, hardy and easy to care for, Michaelmas daisy’s native varieties have survived a long time among ruins and abandoned houses, perhaps even spreading into the wild either by seed or organically, through its rootstock. Michaelmas daisy flowers for a long time, and it isn’t struck down by the first night frost – it is often still in full bloom when the first snow falls. In cool autumns the capitula open very slowly. The long flowering time throughout the autumn is especially important for butterflies that are preparing for winter, which asters attract. Michaelmas daisy also lasts a long time as a cut flower.
Varieties of Michaelmas daisy have been created to suit every taste. A two-tone capitulum is typical of the genus: the disk florets are yellow, while the ray-florets vary between white and red and especially blue and lilac tinges, and in many species all the flowers are the same as the ray-florets. However, these new varieties cannot compare with native varieties as sources of nectar, and they are also more demanding to grow in the garden. Some examples; Siberian aster (name also arctic aster, Eurybia sibirica, earlier Aster sibiricus), Rhone aster (Galatella sedifolia, earlier Aster sedifolius), Alpine aster (Aster alpinus), New England aster (Symphyotrichum novae-angliae, earlier Aster novae-angliae), white wood aster (Eurybia divaricata, earlier Aster divaricatus), New York aster (Symphyotrichum novi-belgii, earlier Aster novi-belgii) and Michaelmas daisy (Symphyotrichum salignum, earlier Aster x salignus).