Also known as American Aster · 3.3k saves
Symphyotrichum
Symphyotrichum, the genus most gardeners know as american aster. We track 29 varieties; the ones most used by real gardeners.
The 24 most-saved Symphyotrichum varieties
See all 29 Symphyotrichum varieties →Search this genus →
9 species of Symphyotrichum
Each one is a parent of the varieties above.
Track your Symphyotrichum in Sow
Save the Symphyotrichum you grow and get care reminders timed to your zone.
How to grow Symphyotrichum
Whats common across all Symphyotrichum varieties in our catalog — drawn from the care records of the 29 most-grown of them.
The Symphyotrichum year
- DivideApril90% of varieties
Divide clumps every 3-4 years to maintain vigor
- Pinch TipsMay and June79% of varieties
Pinch back tips until early June for denser, more compact growth
- Spring CleanupMarch48% of varieties
Cut back old, dead stems to the ground before new growth appears
- Check for PestsJuly–September38% of varieties
Watch for powdery mildew in humid conditions
- PlantApril, May, October and November34% of varieties
Plant transplants in spring or fall.
Do
- Water deeply during dry spells 🌱
- Deadhead spent flowers to encourage more blooms
- Apply mulch to conserve moisture
- Water consistently during dry periods 🌱
- Deadhead spent flowers to encourage reblooming
Avoid
- Avoid overwatering to prevent root rot ❌
- Avoid overwatering, which can cause root rot ❌
- Avoid overhead watering, which can encourage fungal diseases.
- Overwater in winter ❌
What goes wrong with Symphyotrichum
| Problem | What you'll see | What to do |
|---|---|---|
| Aphids | Sticky residue and distorted leaves | Use insecticidal soap or neem oil |
| Powdery Mildew | White powdery coating on leaves | Improve air circulation and apply sulfur-based fungicide |
| Lace Bugs | Leaves appear stippled, yellow, or bleached; tiny dark spots of excrement on undersides. | Spray with insecticidal soap or neem oil, ensuring good coverage of leaf undersides. Encourage beneficial predatory insects. |
| Japanese beetles | Skeletonized foliage and damaged flower buds in mid-summer. | Hand-pick beetles into soapy water or apply organic controls during peak activity. |
| Powdery Mildew | White powdery coating on leaves | Improve air circulation and apply fungicide |
| Powdery mildew | White powdery fungal growth on leaves, leading to lower leaf drop. | Improve air circulation, space plants properly, and apply fungicides if severe. |
| Root rot | Wilting foliage and black, mushy roots in waterlogged soil. | Improve soil drainage and avoid overwatering. |
Making more Symphyotrichum
Division
- Dig up mature plants in early spring or fall
- Separate clumps into smaller sections with roots intact
- Replant divisions at same depth and water thoroughly
- Allow 6 weeks for establishment
Seed
- Tuck seeds into moist soil in early spring; expect germination in 2-3 weeks.
Symphyotrichum questions
How many types of Symphyotrichum are there?
The Sow catalog tracks 29 distinct Symphyotrichum varieties. The most popular — ranked by 3.3k real gardeners — are shown first above.
What zones does Symphyotrichum grow in?
Across its varieties, Symphyotrichum covers USDA Zones 4–10. Individual varieties differ — each plant page lists its exact range, and Sow filters the catalog to your zone automatically.
When does Symphyotrichum bloom?
Most Symphyotrichum varieties bloom in late summer, early fall, late summer to fall. Staggering early, mid, and late varieties extends the genus's season in one bed.
Which Symphyotrichum should I choose?
Start from the most-saved varieties above — popularity across thousands of gardens is a strong signal of reliability — then filter by your zone and sun. In the Sow app you can preview any of them in a photo of your actual yard before you buy.