How to Grow Balloon Flower

closeup of a balloon flower

The Spruce / Autumn Wood

Balloon flower (Platycodon grandiflorus) is a clump-forming perennial flower, a member of the easy-to-grow bellflower family of plants. They are so named because puffy, balloon-like buds swell up to produce the 2- to 3-inch star-shaped flowers.

Balloon flower is a very easy to grow perennial, but tall plants may need staking to keep them from flopping. Blooming all summer long, it is an excellent plant for border gardens or rock gardens, and it freely self-seeds in the garden. The species plant has intense blue-violet flowers, but there are also cultivars with white and pink blooms.

Balloon flower is generally planted in the spring after the danger of frost has passed. It grows quickly to bloom in its first year.

Botanical Name Platycodon grandiflorus
Common Name Balloon flower, Chinese bellflower, Japanese bellflower
Plant Type Herbaceous perennial
Mature Size 1– 2 1/2 feet tall, 1–1 1/2 feet wide
Sun Exposure Full sun to part shade
Soil Type Rich, loamy, medium moisture, well-draining
Soil pH 5.5–7.5 (acidic to slightly alkaline)
Bloom Time Summer
Flower Color Blue-violet, white, pink
Hardiness Zones 3–8 (USDA)
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

Balloon Flower Care

You can start with nursery plants or grow your balloon flowers from seed. Planted in the early spring after the threat of frost has passed, balloon flowers should bloom during their first 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. 

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 outside of root rot in areas with large amounts of rainfall. 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 part shade and might actually prefer some shade from where the afternoon sun is especially hot.

Soil

Balloon flowers prefer organically rich, loamy soil that has good drainage. They don’t grow well in dense soil, such as clay. 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. Balloon flowers tolerate both humid and dry air conditions, provided 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 expend blooming during the growing season. If you have poor soil, use an all-purpose, slow-release fertilizer in early spring.

Balloon Flower Varieties

There are several good 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.
  • P. 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.
  • P. grandiflorus 'Komachi': The purple-blue flowers in this variety remain in their puffy pillow stage.
  • P. 'Sentimental Blue': This dwarf variety grows about 6 inches tall with lots of 1- to 2-inch purple flowers.

Pruning

Pruning generally isn't necessary with balloon flowers, though you can do so 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.

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 a 4-inch length of stem, and remove the lower 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.

How to Grow Balloon Flower From Seed

Start seed indoors in the early spring about six to eight weeks prior to your area's projected last frost date, using seed starter mix or ordinary potting soil. Barely cover the seeds with 1/16 inch of soil. Place the container in a warm location until the seeds germinate. After the weather has warmed, you can transplant the 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.

Article Sources
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  1. Jeon, Chi Sung et al. Root Rot of Balloon Flower (Platycodon grandiflorum) Caused by Fusarium solani and Fusarium oxysporum. The plant pathology journal, vol. 29, no. 4, 2013. doi:10.5423/PPJ.NT.07.2013.0073