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Balloon Flower
Platycodon
Balloon Flower blooms from July through August.
Months here are Northern Hemisphere months; in the Southern Hemisphere, shift them by six months.
Growing Balloon Flower
Plant it in full sun. It prefers moderate water. It is hardy in USDA zones 3–8. Expect it to reach about 24 in tall and 16 in wide at maturity, in roughly 2 years (checked).
No toxicity note is on file for Balloon Flower. That is not a clearance: check its safety for people and pets before planting.
What was checked
Fifteen fields were checked against named botanical sources, each recorded beside the sources that carried it, with every unsettled point written down and decided: mature height and spread, hardiness zones, sun, water, bloom months and color, the trait tags, soil, diseases, pests, toxicity, the plant's own names, and years to mature size, which rests on a recorded house rule where no publisher states one and is marked so. Each fact above carries its own mark. The planting, spacing and size sections are derived from these checked facts by a fixed rule, not checked separately, and the plant type is the library's own classification.
When to plant Balloon Flower
Plant Balloon Flower in early spring as soon as the soil is workable, or in early fall at least six weeks before your first frost, so roots establish in cool weather. In zone 5, the middle of its hardy zones 3 to 8, spring means April to June and fall means August or September. Once settled, it blooms from July to August.
Month-by-month timing for your zone is on the planting calendar; if you garden near zone 5, the middle of this plant's hardy range, start with zone 5 in April. Derived from the plant's category, zones and bloom months plus typical zone frost dates, not checked separately.
How big does Balloon Flower get?
24 intall5 ft 7 inan adult16 inwideSee Balloon Flower in a garden plan: the planner shows it in 3D beside everything else you add, growing toward this size over the years.
How far apart to plant Balloon Flower
Derived from the mature spread above by a fixed rule, not checked separately: spacing is the spread, center to center.
Space Balloon Flower about 16 in apart, center to center, so each plant has room to reach its full width.
Add Balloon Flower to a garden plan and the planner draws it at its full width, so you see the spacing before you buy.
Where these facts come from
Balloon Flower's height, spread, hardiness zones, sun, water, bloom months and color, years to mature size, trait tags, soil, diseases, pests and toxicity were checked against 15 published sources on August 24, 2026. Each one is linked below with every fact it carried, which can include a fact this page still marks as not yet checked, because a source carrying a value is not the same as the value being held to the standard. Facts not in that list, and the planting, spacing and size sections, are not covered by these sources.
- Missouri Botanical Gardenheight, spread, hardiness zones, sun, water, bloom months and color, trait tags, soil, diseases and pests
- RHSRoyal Horticultural Societyheight, spread, sun, water, bloom months and color, years to mature size, trait tags, soil and pests
- NC State ExtensionPlant Toolboxheight, spread, hardiness zones, sun, bloom months and color, trait tags and soil
- University of Illinois ExtensionFlowersheight, hardiness zones, sun, water, bloom months and color and soil
- Proven Winners'Astra Blue'height, spread, hardiness zones, sun and trait tags
- The Morton Arboretumheight, spread, hardiness zones, sun and trait tags
- Walters Gardens'Fuji Blue'height, spread, hardiness zones, sun and trait tags
- Walters Gardens'Sentimental Blue'height, spread, hardiness zones, sun and trait tags
- Missouri Botanical Garden'Fuji White'height, spread, hardiness zones and sun
- Missouri Botanical Garden'Astra Blue'height, spread, hardiness zones and sun
- Swallowtail Garden Seedsheight, hardiness zones, sun and trait tags
- University of Illinois ExtensionHort Answersheight, hardiness zones and sun
- Chicago Botanic GardenPlant Finder, 'Mariesii'hardiness zones and sun
- frontiersin.orgFrontiers in Nutritiontoxicity
- Iowa State University Extensionand Outreach, Yard and Gardensoil
How the checking works, and what each standard covers, is on the verified plants page.
Comes in 5 varieties across 3 colors
Same genus, similar care - pick the color you are growing.
Compare every variety in the Balloon Flower group
Every figure is the variety's own page fact. Tap a name to open it.
| Variety | Color | Blooms | Hardiness | Sun | Size (H × W) |
|---|---|---|---|---|---|
| Astra Double Blue | Blue | Jul–Aug | Zones 3–8 | Full sun | 10 in × 12 in |
| Balloonthis page | Blue | Jul–Aug | Zones 3–8 | Full sun | 24 in × 16 in |
| Fuji Pink | Pink | Jul–Aug | Zones 3–8 | Full sun | 24 in × 16 in |
| Fuji White | White | Jul–Aug | Zones 3–8 | Full sun | 24 in × 16 in |
| Komachi | Purple | Jul–Aug | Zones 3–8 | Full sun | 20 in × 16 in |
| Sentimental Blue | Blue | Jul–Aug | Zones 3–8 | Full sun | 8 in × 12 in |
Good to know about Balloon Flower
Curated from university extensions, botanic gardens and other primary sources, with the source named on every note. A note reports what its source says; where that differs from a fact above, the fact above is this entry's stored value, and its mark says whether it has been checked.
Worth knowing
The name is literal: the buds swell up like little hot-air balloons, then split open into upward-facing star-shaped flowers. Squeeze a plump bud and it pops. per NC State
Does soil pH matter?
NC State calls for slightly acidic soil, while Morton Arboretum says it tolerates alkaline ground. Do not chase a pH number: sharp drainage matters far more than pH here. per NC State and Morton
Plant it once, permanently
It grows from a thick, fleshy taproot that rarely survives digging, so it resents moving or division. Pick its spot for keeps and start new plants from seed. per NC State
Mark the spot in spring
It breaks dormancy very late in spring, so its patch can look empty for weeks. Mark it with a label and avoid digging, hoeing, or weeding over the crown. per Illinois and Missouri Botanical
Roots are eaten in Korea
The fleshy roots are a traditional Korean food called doraji, soaked to cut bitterness, then served in salads, soups, and seasoned side dishes, and used for respiratory complaints. per Nutrients and Frontiers in Pharmacology
Keep tall stems upright
Taller types flop and may need staking. Instead, cut stems back by about half in late May (the Chelsea chop) for shorter, bushier plants that bloom a little later. per Missouri Botanical
What pairs well with Balloon Flower
Good companions share its growing conditions and add something it lacks: an earlier or later bloom, a lower carpet in front, or structure through winter.
Aster
Shares full sun and moderate water; blooms in early fall as this one finishes; its seed heads stand through winter, for structure and the birds; purple sits close to blue on the wheel.
Perennial Sunflower
Shares full sun and moderate water; overlaps, then carries the display into mid fall; its seed heads stand through winter, for structure and the birds; taller at 5 ft, for the layer behind it.
Sea Thrift
Shares full sun and low to moderate water; blooms in mid spring, before this one opens; evergreen, so the bed keeps its shape through winter; lower at 8 in, for the front of the border.
Fountain Grass
Shares full sun and low to moderate water; overlaps, then carries the display into mid fall; its seed heads stand through winter, for structure and the birds; taller at 3.5 ft, for the layer behind it.
Little Bluestem
Shares full sun and low to moderate water; overlaps, then carries the display into early fall; its seed heads stand through winter, for structure and the birds; taller at 3.5 ft, for the layer behind it.
Ninebark
Shares full sun and moderate water; blooms in late spring, before this one opens; taller at 6.5 ft, for the layer behind it; its white flowers settle the blue.
Autumn Crocus
Shares full sun and moderate water; blooms in early fall as this one finishes; lower at 6 in, for the front of the border; purple sits close to blue on the wheel.
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