Troubleshooting
Sky Blue Aster problems — and how to fix them
Sky Blue Aster (Symphyotrichum oolentangiense) is generally forgiving once you match its basics, but a few issues come up again and again. Here is what each one looks like, why it happens, and the fix.
Flopping in rich or moist soil
Adapted to lean, dry ground, it lodges when overfed or overwatered. Grow it hard in poor, well-drained soil and full sun for self-supporting stems.
Root rot in wet soil
Poor drainage and standing moisture rot the crown of this drought-adapted species. Plant in sharply drained soil and never let it sit waterlogged over winter.
Powdery mildew
Possible in humid, crowded, or shaded conditions. Provide full sun and open spacing; its prairie origins make it fairly resistant when grown in the right dry, airy site.
Sparse bloom in shade
Too little sun yields lanky stems and few flowers. Relocate to a fully sunny, open position to restore its characteristic cloud of azure daisies.
Prevent sky blue aster problems before they start
Most sky blue aster issues are care-mismatch, not bad luck. Dial in the basics:
Looking for sky blue aster in general rather than its problems? Read the full sky blue aster care guide — light, water, soil and feeding.
Sky Blue Aster problems — FAQ
Why is my sky blue aster flopping in rich or moist soil?
Adapted to lean, dry ground, it lodges when overfed or overwatered. Grow it hard in poor, well-drained soil and full sun for self-supporting stems.
Why is my sky blue aster root rot in wet soil?
Poor drainage and standing moisture rot the crown of this drought-adapted species. Plant in sharply drained soil and never let it sit waterlogged over winter.
Why is my sky blue aster powdery mildew?
Possible in humid, crowded, or shaded conditions. Provide full sun and open spacing; its prairie origins make it fairly resistant when grown in the right dry, airy site.
Why is my sky blue aster sparse bloom in shade?
Too little sun yields lanky stems and few flowers. Relocate to a fully sunny, open position to restore its characteristic cloud of azure daisies.