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Astra Blue
Astra Series; dwarf selection
At‑a‑glance
- Group/Class: Astra Series; dwarf selection
- Height × spread: 8-22 in (20-55 cm) × 12-24 in (30-60 cm)
- Bloom window: early July to early September
- Color & flower form: violet-blue; single, star-shaped from balloon buds
- Fragrance: 0 none
- USDA hardiness: zones 3-8
- Breeder / Year / Origin: unknown
- Cut-flower notes: firm stems; sear cut ends at harvest to prevent sap bleed; holds when conditioned
- Pet safety: unknown
How it differs
- Shorter and bushier than typical balloon flower.
- Earlier to bloom than many tall strains.
- Seed-grown lines can vary in height and width.
- Stems are more self-supporting in summer than taller types.
Strengths
- Compact habit for containers and edging.
- Long summer bloom with regular deadheading.
- Cold hardy into northern zones.
- Generally low pest and disease pressure.
Care in one minute
Site: full sun to light shade with wind exposure limited for taller stems.
Soil: deep, fertile, well-drained loam; slightly acidic to neutral pH.
Water: keep evenly moist; avoid soggy conditions.
Feeding: light spring feeding; excess nitrogen encourages flop.
Grooming: deadhead to extend bloom; cut stems back by half in late spring if height control is needed.
Overwintering: mulch lightly after frost; mark clumps because shoots emerge late.
Watch‑outs
- Seed strains may grow taller than listed.
- Stems can relax by early fall if grown in partial shade.
- Crowns resent disturbance once established.
Best uses (tags)
Provenance note
The Astra line is a modern seed series selected for compact growth. Independent trials documented size variability in seed-grown plants.
References
- Chicago Botanic Garden – A Comparative Study of Platycodon grandiflorus Cultivars (2009)
- Missouri Botanical Garden – Platycodon grandiflorus (Plant Finder)
- NC State Extension – Platycodon grandiflorus profile
- RHS – Platycodon grandiflorus species profile
