A group of bushy, late flowering, herbaceous perennials with narrow green leaves covered by clouds of daisy-like flowers; either singly or in sprays. The name of this useful late flowering plant is taken is from the Latin word meaning star - indicating the shape of its showy flower heads, borne in profusion from late summer onwards.
Family: Asteraceae (daisy)
Botanical Name: several species of this plant have now been reclassified, see the popular varieties list below.
Common Names: Michaelmas daisy, New York Aster, Fall Asters.
Foliage: Deciduous. Narrow, dark green, leaves. Faintly aromatic.
Flowers: Clusters of daisy-like flowers, in shades of white, pink, red, blue, mauve or purple, with yellow-centres (depending on variety). Single, double or semi-double forms are available.
Flowering Period: Late-summer to late autumn.
Soil: Moist but well-drained moderately fertile soil. Chalk, sand or loam. Alkaline or neutral pH. Most varieties thrive best in alkaline soils.
Conditions: Full sun. South, west or east facing, in an open sunny location.
Habit: Compact, upright and bushy.
Type: Herbaceous perennial.
Hardiness: Most varieties are fully hardy in the UK.
Origin: Native to Asia, Europe and North America.
These useful late summer to early autumn perennials are tolerant of most conditions except drought. All varieties prefer an open sunny or partially-shaded spot, in a fertile and moist but well-drained soil. A selection of one or more of these late flowering beauties will keep your garden blooming well into in autumn.
Plant in sunny beds and borders, in groups of two or more, for maximum impact. A good choice for coastal, cottage, informal and wildlife gardens.
Useful for cut flowers when little else is available in the garden.
Easy to grow and propagate. Needs very little care and attention if growing conditions are ideal. Certain varieties can be a little invasive, as clumps can quickly spread and/or self seed around the borders.
Stake taller cultivars securely. Shorter varieties usually require little or no support.
Because they flower late they can often be overlooked during hot dry summers. So keep them well watered and don't allow the soil to totally dry out or flowering will suffer. However, avoid waterlogged conditions.
Cut down flower stems after flowering.
Susceptible to slugs, snails, eelworms and aphid attack. Prone to wilt, leaf spot and grey moulds, especially if conditions are too dry or there is not enough free air flow through the plants. Older plants are more susceptible to powdery mildews, so it is often best to lift and divide older specimens to reinvigorate them.
Asters are prolific self-seeders but named varieties will not come true from seed.
Easy to propagate from division. Divide mature clumps between late autumn and spring, or take basal or softwood cuttings in the spring.
A large volume of plants can be produced by teasing out a clump into single rooted shoots and planting up in spring, 5cm/6in apart.
There over 500 cultivars of Aster are available, ranging in height from tall erect plants to compact low domes, in a wide range of flower colours and forms.
A. amellus (Italian aster, European
Michaelmas-daisy) slow-growing. Flowers appear in loose
clusters 2in (5cm) across, in shades of pink, blue
or mauve with yellow centres. August-September. Height
2ft (60cm), spread 1ft (30cm).
Good cultivars include: 'King George' large, violet-blue blooms and 'Pink Zenith' rich pink blooms
A. lateriflorus has masses of attractive tiny flowers and long-season colour. Attracts butterflies. Height: 1 to 3ft (30 to 90cm). Useful cultivars include: Aster lateriflorus ‘Lady in Black’ with dusky purple leaves covered in clouds of tiny, white, purple-centred flowers, and Aster lateriflorus 'Prince' with white daisy like flowers with pinkish centres.
A. thomsonii a clump-forming perennial, with oval toothed leaves. Lavender-blue flowers with yellow centres. Earlier flowering. Height to 3ft (1m).
A. x frikartii is bushy with dark-green pointed leaves. Clusters of lavender-blue flowers, 3in (7.5cm) across, with yellow centres appear from July to September. Height 3ft (90cm), spread 1.5ft (50cm). A. X frikartii ‘Monch’ is more compact variety. Height 75cm (30in).
Galatella sedifolia (syn Aster acris) forms a round dome of erect stems with narrow, pointed, hairy green leaves. Usually with star-shaped, light mauve flowers, with yellow centres. Height 3ft (90cm), spread 1.5ft (50cm). August to September.
Symphyotrichum novi-belgii (New
York aster) was formerly included
within the genus Aster but now reclassified. This
form has simple, lance-shaped leaves and daisy-like
flower heads. Height up to 2ft (60cm). Flowers September
to October. Popular cultivars include:
‘Fellowship’ large pink flowers
‘Royal Velvet’ deep violet flowers
‘Royal Ruby’ deep red flowers
‘Little Pink Beauty’ dwarf with pink flowers
Symphyotrichum novae-angliae (New England aster) is a tall form with light-green pointed leaves and woody stems. Flowers appear in clusters of pink or rose-red, from September to October. Height up to 4-5ft (1.2-1.5m), spread 2ft (600mm). Good for cutting. Useful cultivars include: 'Harrington's Pink' and 'Alma Potschke' (deep rose).