Balloon Flower Plant Profile

closeup of a balloon flower

The Spruce / Autumn Wood

Balloon flowers (Platycodon grandiflorus) are part of the easy-to-grow bellflower family. While they are sometimes commonly referred to as bellflowers, their flower is really more of a star shape and about 2 to 3 inches wide in shades of blue-violet, white, and pink. It's the bud, which puffs up and bursts open into a flower, that gives the plant its common name of balloon flower. These small plants grow either solo or in clusters and feature short, blue-green leaves. They ideally should be planted in the spring and will generally grow quickly to bloom in their first year.

Botanical Name Platycodon grandiflorus
Common Name Balloon flower, Chinese bellflower, Japanese bellflower
Plant Type Herbaceous perennial
Mature Size 1 to 2.5 feet tall and 1 to 1.5 feet wide
Sun Exposure Full sun to part shade
Soil Type Rich, loamy, medium moisture, well-draining
Soil pH 5.5 to 7.5
Bloom Time Summer
Flower Color Blue-violet, white, pink
Hardiness Zones 3 to 8
Native Area China, Korea, Japan, Russia
balloon flowers in different stages of opening
​The Spruce / Autumn Wood 
closeup of a balloon flower
​The Spruce / Autumn Wood
cluster of balloon flowers
The Spruce / Jordan Provost
Japan, Nagano Prefecture, Balloon Flowers (Platycodon grandiflorus) and Golden Lace (Patrinia scabiosifolia) flowers
Fumio Tomita / Getty Images

How to Grow Balloon Flowers

You can start with nursery plants or grow your balloon flowers from seed. Plant nursery balloon flowers in your garden in the early spring after the threat of frost has passed. They should bloom during that season. However, you also can plant them later in the growing season (spring to fall), though you might not get blooms until their second year. 

Start seed indoors in the early spring about six to eight weeks prior to your area's projected last frost date. After the weather has warmed, you can transplant your seedlings outdoors. If you plant seeds directly in your garden, do so after your last frost date and know they likely won't flower in their first year.

These perennials will come back year after year in the garden and will self-sow their seed, though they aren't aggressive spreaders. Overall, balloon flowers are fairly low-maintenance plants and are quite pest- and disease-resistant. The taller varieties of balloon flowers can become a bit floppy. You can stake them or plant them in clumps to let them support one another.

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Watch Now: How to Grow and Care for Balloon Flowers

Light

You will get the most flowers if you plant balloon flowers in full sun (at least six hours of sunlight on most days). However, they will be fine in partial shade and might actually prefer some shade from especially hot afternoon sun.

Soil

Balloon flowers prefer organically rich, loamy soil that has good drainage. They don’t grow well in dense soil, such as clay. Plus, they like a soil pH in the 5.5 to 7.5 range.

Water

Keep the soil of young plants consistently moist but not soggy. Once established, balloon flowers like a moderate amount of moisture in the soil, but they can tolerate short periods of drought. They won’t need a lot of supplemental watering unless you have a long period without rainfall that causes the soil to dry out.

Temperature and humidity

Balloon flowers are hardy and do well in USDA growing zones 3 to 8. Their ideal temperature range is between 60 and 80 degrees Fahrenheit, but they can withstand higher temperatures if they have some shade in the afternoon. Frost can kill young plants and will cause established plants to die back into the ground in the fall. Furthermore, balloon flowers are fairly tolerant of humidity, along with dry conditions, as long as they have the right amount of soil moisture.

Fertilizer

Balloon flowers typically don't need supplemental feeding if you have rich soil. But a layer of compost in the fall can help them replenish the energy they expended blooming during the growing season. If you have poor soil, use an all-purpose, slow-release fertilizer in the early spring.

Propagating Balloon Flowers

Propagating by division is generally not recommended for balloon flowers because the root system is fragile and doesn't like being disturbed. Instead, you can propagate by taking stem cuttings. Use clean pruners to trim approximately a 4-inch length of stem, and remove the lower half of foliage to expose the bare stem. Use a rooting hormone on the bare stem if you wish, and then pot it in moist soil.

Keep the soil moist (but not soggy) as you wait for roots to take hold. Once you see leaf growth and feel resistance when you give the cutting a gentle tug, you’ll know roots have grown. Then, the plant is ready to be transplanted into the garden.

Pruning

Pruning generally isn't necessary and more for appearance. To achieve stockier plants, you can cut back tall stems by about half in the late spring. This can help to prevent the plants from flopping over. Also, deadheading your plants (removing spent blooms) will keep them looking good and repeatedly blooming. Don't remove the whole stem, just the faded flowers. The remaining buds on the stem will continue to open.

Varieties of Balloon Flowers

There are several varieties of balloon flowers, including:

  • Platycodon grandiflorus Astra series: These have double flowers with 10 petals in blue, pink, or white. They're a good choice to start from seed.
  • Platycodon grandiflorus Fuji series: These are the most commonly sold varieties, as well as the tallest with 30-inch stems and flowers in blue, pink, or white.
  • Platycodon grandiflorus 'Komachi': These have purple-blue flowers that remain in their puffy pillow stage.
  • Platycodon grandiflorus 'Sentimental Blue': This dwarf variety grows about 6 inches tall with lots of 1- to 2-inch purple flowers.