Balloon flower
Platycodon grandiflorus · Campanulaceae
Buds like small inflated balloons pop open into wide, star-shaped bells of violet-blue, white or pink in midsummer. It is long-lived and slow to appear in spring.
- Size
- 24 in tall, 14 in wide
- Zones
- 3 to 8
- Light
- Full sun to part sun
- Flowers
- Early July to mid August
- Pets
- No toxicity recorded
- Job in a bed
- Drift
A bed built around balloon flower
The planner designed this bed around balloon flower when this page was made: a 12 × 6 ft (3.7 × 1.8 m) English border in zone 6, full sun. It chose the other plants from the 966 that suit those conditions, and says below why balloon flower stands where it does.
The plants
- 1 Balloon flower × 8, blue
- 2 Candytuft × 3, white
- 3 Sedum 'Lidakense' × 19, pink
- 4 Brown-eyed Susan × 5, yellow
- 5 Foxglove beardtongue × 3, white
- 6 Arborvitae 'Mr. Bowling Ball' × 1, grey-green leaves
- 7 Schubert's allium × 2, pink
- 8 Grecian windflower × 8, blue
Why this plant
- The only bells. The others are dense clusters, daisies, spires and others. Shape reads at a distance, where colours blur.
Why here
- In the middle. At 24 in it is the step between candytuft (10 in) in front and arborvitae 'Mr. Bowling Ball' (2½ ft) behind: each is seen over the one before.
- 8 plants in 2 groups (5 and 3). Seen again further along, the same plant ties the bed together.
Why now
- In flower for 7 weeks. From early July to mid August.
- Fills a gap. For three of those weeks nothing else on the plan is in flower.
Planned as an English border: 6 of the 7 groups (86%) are drifts, longer along the bed than they are deep. Sedum 'Lidakense' is planted in five places along the bed, which gives it rhythm. Sedum 'Lidakense' is the plant there is most of: 19 of the 49.
The planner's own design check: 11 Excellent, 6 Good. It flags one thing to watch: Nothing on this plan is highly poisonous or an aggressive spreader.
Open this bed in the planner Change its size, the sun or the style, move plants about, or swap one for another.
Where balloon flower goes in a border
At 24 in it belongs in the middle of a bed. In the planner's ten height classes it is medium short (18 to 24 in).
Its job: drift. Planted in a small group of three or five, and repeated further along in the other number.
A dependable summer blue once the delphiniums are over. Mark its place, because it comes up very late, and never move it: the carrot-like root resents disturbance.
- Blue for midsummer
- Cottage gardens
- Fun for children
What to plant with balloon flower
Plants recorded as good partners for it, and what each pairing does:
- Shasta daisy 'Becky': in flower together for seven weeks, from early July; tall enough (3½ ft) to stand behind it.
- Daylily 'Stella de Oro': blue against yellow, opposite each other on the colour wheel, if you choose those colours, in flower together for seven weeks; low enough (14 in) to stand in front of it.
- Threadleaf coreopsis 'Moonbeam': blue against yellow, opposite each other on the colour wheel, if you choose those colours, in flower together for seven weeks.
Questions about balloon flower
Does balloon flower need sun or shade?
Balloon flower grows in full sun (6 or more hours of direct sun a day) and part sun (4 to 6 hours of sun, including some afternoon sun).
It wants ordinary well-drained soil, of average fertility, and a good soak in dry spells.
What zones does balloon flower grow in?
USDA zones 3 to 8. It is hardy to zone 3, which means it survives winter nights down to about −30 °F (−34 °C).
Above zone 8 it struggles: the zones measure winter cold, but a plant's top zone usually means the summers are too hot or the winters too mild for it to rest.
Gardening in Canada? Use the USDA zone for your town: Canada's own zone map uses different numbers.
When does balloon flower flower in my zone?
In zone 5 it flowers early July to mid August. As a summer flower it moves about half a week for every zone: earlier where it is warmer.
| Zone 3 | Mid July to late August |
|---|---|
| Zone 4 | Mid July to late August |
| Zone 5 | Early July to mid August |
| Zone 6 | Early July to mid August |
| Zone 7 | Late June to early August |
| Zone 8 | Late June to early August |
Worked out from Hopkins' bioclimatic law: spring arrives about four days later for each degree of latitude north, and one zone is roughly two degrees. A warm spring or a cold one moves any garden two weeks either way.
How far apart should balloon flower be planted?
12 in (30 cm) apart, from the middle of one plant to the middle of the next. That is a little closer than its full width of 14 in (35 cm), so a group knits into one patch.
It grows 24 in (60 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many balloon flower plants do I need?
At 12 in apart, set out in staggered rows:
- 12 to fill 10 square feet (about 1 m²)
- 11 for a single row 10 ft (3 m) long
- 38 to fill a 4 × 8 ft bed on its own
In a mixed border, plant it as a group of three or five, with a second group further along in the other number.
In the bed above, the planner used eight in two groups.
Is balloon flower poisonous to dogs and cats?
No toxicity is recorded for dogs, cats, horses or people, according to NC State Extension.
"Not toxic" is not "edible": a pet that eats a lot of any plant can be sick.
Is there a native plant like balloon flower?
Balloon flower comes from China, Korea, Japan, Russia. These North American natives come closest to doing its job:
- Bottle gentian: the same job in a bed and the same colour; 4 in shorter, flowers late August to early October.
- Wild lupine: the same job in a bed and the same colour; 4 in shorter, flowers mid May to late June.
Matched the way the planner's Swap button matches plants: the same job in a bed, then size, then flowering time.
Do deer eat balloon flower?
They may. NC State does not list it as resistant to deer or rabbits. Where they visit, protect it, or plant it among ones they avoid.
What flowers after balloon flower?
Balloon flower is over by mid August. These start as it finishes and carry the same spot on, so it never goes flat:
- Lilyturf: from early August to mid September, 16 in tall, to stand in front of it and cover its fading stems.
- Garden chrysanthemum: from mid September to late October, 24 in tall.
- Japanese anemone: from mid August to early October, 3 ft tall.
What does balloon flower look like in winter?
Balloon flower dies down to the ground and there is nothing to see until spring. The old stems can be cut in autumn, or left until spring as shelter for overwintering insects.
More Platycodon
- Balloon flower 'Sentimental Blue' Platycodon grandiflorus 'Sentimental Blue'
In these guides
Zone guides: Zone 3 · Zone 4 · Zone 5 · Zone 6 · Zone 7 · Zone 8
Every fact on record
- Type
- Perennial
- Size
- 24 in (60 cm) tall, 14 in (35 cm) wide
- Plant
- 12 in (30 cm) apart
- Height class
- Medium short (18 to 24 in)
- Place in the bed
- Middle
- Flowers
- Early July to mid August; hanging bells; blue, white, pink
- Leaves
- Medium texture, herbaceous; blue-green
- Shape
- Upright, clumping
- Hardy in
- USDA zones 3 to 8
- Light
- Full sun, part sun
- Soil
- Average, well-drained
- Water
- Moderate
- Feeding
- Light, in spring
- Family
- Campanulaceae
- Comes from
- China, Korea, Japan, Russia
Checked against NC State Extension. Flowering times are for zone 5: later in colder zones, earlier in warmer ones. Toxicity and spread information is a general gardening guide, not veterinary or medical advice, and invasive status varies by region. If a person or pet eats a plant, contact poison control or a vet. Check your local invasive species list before planting anything with a spread warning.