Sky Blue Aster
Symphyotrichum oolentangiense (Aster azureus)
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Sky Blue Aster is backordered and will ship as soon as it is back in stock.
Plant Sentry™
Plant Sentry™

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Your order is protected by our compliance system that:
- Prevents restricted plants from shipping to your state
- Ensures plants meet your state's agricultural requirements
- Protects gardens from invasive pests and diseases
Delivery and Shipping
Delivery and Shipping
Delivery and Shipping
Fast, Safe Plant Delivery
Ships in 3-4 business days • Tracking provided • Weather protected
Under $50 | $9.99 |
$50 - $99.99 | $14.99 |
$100 - $149.99 | $16.99 |
$150+ | $24.99 |
✓ Zone-specific timing • ✓ Professional packaging • ✓ Health guarantee
Understanding Plant Options
Nature Hills offers plants in two main formats:
- Container Plants: Grown in pots with soil, sized by container volume and plant age
- Bare Root Plants: Dormant plants without soil, sized by height measurements
Container Plant Sizes
Container sizes indicate plant age and growing capacity rather than liquid volume equivalents. Our containers follow industry-standard nursery "trade gallon" specifications, which differ from standard liquid gallon measurements.
Young Plants (6 months to 18 months old)
Container Size | Actual Volume | Metric Equivalent |
---|---|---|
2" x 2" x 3" | 0.18 - 0.21 dry quarts | 0.20 - 0.23 dry liters |
4" Container | 0.31 - 0.87 dry quarts | 0.35 - 0.96 dry liters |
4.5" Container | 0.65 dry quarts | 0.72 dry liters |
6" Container | 1.4 dry quarts | 1.59 dry liters |
1 Quart | 1 dry quart | 1.1 dry liters |
5.5" Container | 1.89 dry quarts | 2.08 dry liters |
Established Plants (18 months to 2.5 years old)
Container Size | Actual Volume | Metric Equivalent |
---|---|---|
2 Quart | 2 dry quarts | 2.2 dry liters |
#1 Container | 2.26 - 3.73 dry quarts | 2.49 - 4.11 dry liters |
5" x 5" x 12" | 3.5 - 4.3 dry quarts | 3.85 - 4.74 dry liters |
Mature Plants (2-4 years old)
Container Size | Actual Volume | Metric Equivalent |
---|---|---|
#2 Container | 1.19 - 1.76 dry gallons | 5.24 - 7.75 dry liters |
#3 Container | 2.15 - 2.76 dry gallons | 8.14 - 12.16 dry liters |
Large Plants (3-5 years old)
Container Size | Actual Volume | Metric Equivalent |
---|---|---|
#5 Container | 2.92 - 4.62 dry gallons | 12.86 - 20.35 dry liters |
#6 Container | 5.25 - 6.01 dry gallons | 23.12 - 26.42 dry liters |
#7 Container | 5.98 - 6.53 dry gallons | 26.34 - 28.76 dry liters |
Bare Root Plants
Bare root plants are sold by height from the root system to the top of the plant. Plants may exceed minimum height requirements.
Common Sizes:
- Trees: 1 foot, 2 feet, 3 feet, 4 feet, 5 feet, 6 feet
- Shrubs & Perennials: 1 foot, 18 inches, 2 feet
Important Notes
Container Volume Specifications
- Trade Gallon Standard: Our containers follow industry-standard "trade gallon" specifications established by the American National Standards Institute (ANSI Z60.1) for nursery stock
- Volume Variations: Actual soil volume may vary due to plant root systems and growing medium settlement
- Age Indicators: Container size primarily indicates plant age and maturity rather than liquid volume equivalents
Growing Conditions
- Plant size can vary based on variety and growing conditions
- Container size helps indicate plant maturity and establishment level
- Larger containers generally mean more established root systems and faster landscape establishment
Seasonal Availability
- Bare root plants are available seasonally when dormant
- Container plants are available throughout the growing season
- Specific varieties may have limited availability in certain sizes
Questions?
For questions about specific plant sizes or availability, please contact our plant experts who can help you choose the right size for your landscape needs.
Plant Highlights
Sky Blue Aster highlights at a glance!
Specifications
Specifications
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Brand
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Botanical Name
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Growing Zones
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Mature Height
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Mature Spread
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Sun ExposureFull Sun
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Moisture
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Soil
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Growth RateMedium
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Flower Color
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Pollinator Friendly
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Pollinator Required
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Bloom PeriodSummer, Fall

Growing Zones 3-8
Lovely Light Blue Fall Perennial
- Native Selection
- Butterfly Magnet
- Fall Blooms
The best landscapes shine in every season, but that does take careful planning. Asters are a beautiful, sweet blue daisy-shaped flower that blooms from late August into October.
After the heat of the summer, fall is a wonderful time to enjoy your backyard! Plan for these cooler days with flowers that shine in the later part of the growing season.
Sky Blue Aster (Aster azureus, or Symphyotrichum oolentangiense - whew!) is a North American native wildflower, carefully grown by our expert growers. In the wild, it grows along the edge of woodlands and loves the full sun of the open prairie.
In your garden, plant in the middle of your border.
It features an airy texture, so you'll want to plant shorter, sturdy groundcover in front, and taller, coarse perennials or small shrubs. You'll love the way it seems to "float" between rougher textures.
And you aren't the only one who will love it. Butterflies rely on these late-season nectar sources. Monarchs need fuel for their long migratory journey.
Consider including a collection of Asters in your landscape or use in summer container gardens as lovely "Fillers". You'll also love using these for cut flowers inside your house.
Order this rare find today!