Symphyotrichum novi-belgii Seeds | New York Aster
LATIN NAME: Symphyotrichum novi-belgii
COMMON NAME: New York Aster
Plant Profile
The New York aster is a perennial of damp meadows and marsh edges in eastern North America, growing sixty to one hundred and twenty centimetres tall on slender, branching stems. It spreads by rhizomes into a loose clump, and from August to October it carries many flower heads two to three centimetres across, with violet-blue to pale lilac rays and a yellow centre that turns red as it ages.
The leaves are narrow, smooth and dark green, and the lower ones often wither before flowering, which is why the plant can look leggy at the base. It is one of the parents of the large group of garden asters known as the New York hybrids, which flower in every shade from white to deep purple. The species was first described from material collected near New York.
Science & Biotechnology
The plant was long known as Aster novi-belgii, the aster of New Belgium, the name the Dutch gave to their North American colony, which became New York. The great split of the genus Aster in the 1990s moved the North American species into Symphyotrichum, leaving the name Aster for the Eurasian group, and the change was based on chromosome counts and on molecular data rather than on appearance.
The New York aster is a polyploid complex, with several chromosome races that behave as separate species in the wild, and the garden hybrids are a further tangle of crosses with Symphyotrichum laeve and S. dumosum. The plant is a late source of nectar and pollen, and it is one of the flowers that migrating monarchs rely on in autumn as they move south.
Uses & Benefits
New York asters are planted for the autumn border, where their blue and violet flowers carry the garden after the dahlias have finished, and they are one of the best plants for extending the season for pollinators. They are also used in a meadow garden and at the edge of a pond, since they tolerate wet soil.
The taller forms need staking, or the Chelsea chop, cutting the stems back by a third in late May, which makes them bushier and delays flowering by a couple of weeks. Mildew is the main problem in dry summers, and the species is more susceptible than the hybrids. The plant has no edible use, and its medicinal record is slight: the North American asters were used by some peoples for skin complaints, but they are not a significant remedy.
Growing from Seed
Aster seed is short-lived and should be sown fresh in autumn or stratified for three weeks at 4 °C. Surface-sow on a light compost, press in and cover with a little vermiculite, and keep at 18-20 °C; germination takes two to four weeks. Prick out the seedlings as soon as they are large enough, since they grow quickly, and pot them on into a loam-based mix.
Plant out in spring or autumn in moist but well-drained soil in full sun; the plant tolerates part shade but flowers better with light. Water through the first summer. Cut the stems back in late May to reduce height, and divide the clumps every two or three years in spring, discarding the woody centre, to keep the plants vigorous and free of mildew.
Our Take
The best blue in the autumn border, and a lifeline for late bees and migrating butterflies. Divide it every few years to keep it clean.
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