Perennial
Michaelmas daisy
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Flowers | Flowers in September | Flowers in October | ||||||||||
| Plant | Plant in March | Plant in April | Plant in October | |||||||||
| Prune | Prune in May | Prune in November | ||||||||||
| Looks good | Looks good in September | Looks good in October |
Overview
These North American asters, now classed as Symphyotrichum, carry clouds of yellow-eyed daisies in lilac, purple, pink and white just as the rest of the border fades. Butterflies such as red admirals and late bumblebees rely on them. Classic New York asters like 'Marie Ballard' and 'Fellowship' are lovely but prone to mildew. If that worries you, try New England asters (Symphyotrichum novae-angliae), such as 'Harrington's Pink', or Aster × frikartii 'Mönch', which are generally healthier.
Where to grow michaelmas daisy
Plant in sun or light shade in soil that does not dry out in late summer; clay is fine. Compact dwarf forms around 30 cm tall suit the front of a border or pots, while taller ones belong at the back.
Planting
Plant in spring, or in autumn straight after flowering, about 45–60 cm apart. Give each clump space so air can circulate between plants.
Care through the year
Spring
Divide clumps and mulch with compost after rain.
Summer
Water in drought; dry roots are the main trigger for mildew.
Autumn
Enjoy the flowers, then cut stems down when they turn brown.
Winter
Leave a few stems standing for overwintering insects if tidy looks are not a priority.
Pruning
Shear tall varieties back by a third in late May to make them bushier and less floppy. Otherwise, cut everything to near ground level after flowering.
Propagation
Divide every two or three years in spring, replanting only vigorous young pieces from the outer edge. Basal cuttings root easily in spring.
Common problems
Powdery mildew is common on New York asters; mulch, water and thin crowded stems. Wilting shoots on otherwise healthy clumps should be cut out and binned. Slugs eat young growth in spring.
Guides to the problems most likely to affect michaelmas daisy:
Something else wrong? Diagnose it by symptom.
Month-by-month reminders
Jobs for this plant come round in March, April, May, October and November. Each month page lists everything else worth doing in the garden at the same time.
Related plants
Sources
Botanical names follow Kew's Plants of the World Online; growing attributes were checked against the references below. Text is our own. See our editorial policy.