Aster (New York) Growing Guide

Symphyotrichum novi-belgii and hybrids

Aster (New York)

Crop Rotation Group



Fertile, well-drained soil enriched with compost, with a slightly acidic pH.


Full sun.

Frost tolerant

Well-rooted plants are hardy to -34°C (-30°F).


Drench with a liquid organic fertiliser when plants begin to grow tall in late spring or early summer. When growing autumn asters in containers, feed again in midsummer using a high phosphorous fertiliser intended to support strong blooming.


Single Plants: 30cm (11") each way (minimum)
Rows: 30cm (11") with 30cm (11") row gap (minimum)

Sow and Plant

New York asters can be grown from seed year round in containers but require 60 days of cold stratification, otherwise in cool climates they can be direct sown in autumn and winter and will germinate in spring. The heavy-blooming improved cultivars are propagated vegetatively, by division or by rooting stem cuttings. Look for tall varieties for planting in spring, or obtain cuttings and root them in moist potting soil. Dwarf plants grown in containers are widely available in late summer, timed for autumn display. Young plants need water when they are actively growing, but avoid keeping the plants too wet.
Our Garden Planner can produce a personalised calendar of when to sow, plant and harvest for your area.


Tall varieties benefit from being pinched back in early summer to stimulate the growth of strong, bushy branches. Many new dwarf varieties do not require pinching.


New York asters make good filler for cut arrangements, though their vase life is short.


Powdery mildew is not unusual late in the season, but it is not severe enough to kill the plants.

Planting and Harvesting Calendar

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Pests which Affect Aster (New York)