How to Grow Blue Balloon Flower (Platycodon Grandiflorus) Plants?

The Blue Balloon flower (Platycodon Grandiflorus) is a species of perennial herbaceous flowering plant in the Campanulaceae family. In fact, this plant is the only member of the Platycodon genus.

Indigenous to East Asia (Japan, Korea, China, and far east Russia), it has several local names. They include Chinese bellflower and Japanese bellflower. Most of its names are referred to its balloon-shaped flower buds.

This article focuses on the blue balloon flower (Platycodon Grandiflorus), its description, propagation, caring, varieties, and uses.

Due to its disease resistance, hardiness, and easy to grow characteristics, gardeners all over the world, including the USA love to grow them. These long-living plants are deer-resistant too. Naturally, these plants grow in dense clumps. Hence, they fit perfectly as border plants.

Description of Blue Balloon Flower Plants

Generally, the blue balloon flower (Platycodon Grandiflorus) plant grows about 60 cm (24 in) in height and spread about 30 cm (12 in) wide. With serrated margins, the lance-shaped thick leaves are dark green in color.

Photo by Kurt Stüber ( Wikimedia Commons) (CC BY-SA 3.0)

During summer, the balloon-shaped swollen flower buds sprout out on stems. Resembling upturned bells in a star-like shape, they open up to form 2- 3-inch beautiful blue flowers. Sometimes the shades may vary from blue to pink and white. some flowers have even display prominent veins on their petals.

Being fleshy, the taproots are prone to damages when handled roughly.

In native lands, the true botanical species can grow tall exceeding 36 inches in height and about 18 inches wide, particularly in the wild.

In commercial markets, you can find several cultivated varieties. The dwarf plants grow about 4 – 6 inches tall and similarly wide. Medium-sized specimens grow about 12 -18 inches tall and spread similarly.

Propagation of Blue Balloon Flower Plants

Blue Balloon flower - Propagation

Photo by  Kurt Stueber ( Wikimedia Commons) (CC BY-SA 3.0)


These plants prefer to grow under full sun. However, they need partial shades in dry, hot afternoons. These plants bloom more when exposed to at least six hours of direct sunlight, most of the days.

Temperature and humidity

The blue balloon flower (Platycodon Grandiflorus) plant thrives well in USDA Zones 3-8. The ideal temperature range to grow these plants is between 60 – 80 F. However, these hardy plants can withstand somewhat higher temperatures when you provide them with afternoon shades.

During winters, the frost kills young plants. It also causes dieback in well-established plants. As a result, they fall on the ground and ruin out completely.


Ideally, these plants prefer to grow in organically rich, moderately moist, well-draining loamy soils with a pH range between 5.5 – 7.5. Dense soils, such as sand, silt, or clay are not preferred to propagate these herbaceous perennials.

By maintaining the soil moisture proportionately, you can encourage them to tolerate both dry and humid air conditions.

From Seeds

As there is almost “zero stress” on delicate roots, this is the best propagation method for the blue balloon flower (Platycodon Grandiflorus) plants.


If you prefer the plants to bloom in the first year, start propagating them indoors. Start this process 6 – 8 weeks before the average last spring frost date in your area.

1.) Fill a pot with potting soil or seed starter mix. Place the seeds in the pot and barely cover them with soil (about 1/16 inch). Be aware, these seeds require light to germinate.

2.) Maintain the soil moisture by misting or applying small amounts of water proportionately. But avoid overwatering.

3.) Place the pot in a warm location. You can expect the seedlings to emerge within a few weeks.

4.) After the risk of frost is passed and after the seedlings sprout out at least a couple of true leaf sets, harden them off for 3-5 days.

5.) Without damaging the fragile roots, carefully transplant them in gardens. To minimize the transplant stress, maintain the seedlings’ soil surface evenly with ground soil surface while transplanting.


After the average last spring frost date, you can also sow the seeds directly in the garden. But they may not bloom in the first year of propagation.

1.) After moistening the soil surface, just sprinkle the seeds a few inches apart through the entire planting area.

2.) Although covering is not required, you can gently press the seeds in the soil (about 1/16 inch deep) with your fingers.

3.) Maintain the moisture by light application or misting of water. But avoid overwatering.

4.) The seedlings will emerge within a few weeks. After a few true leaf sets have formed, thin the seedlings with respect to their mature dimensions.

Nursey Plants

This is another easy method of propagating blue balloon flower (Platycodon Grandiflorus) plants.

You can purchase nursery-grown young plants from nearby garden centers. For the first-year flowering, transplant them in the early spring to your gardens. For second-year flowering, you can transplant them anytime during the growing season.

Dig a hole just as wide as and as deep as the root ball. After carefully removing it from the pot, place the young plant in the dug hole. Fill back the soil maintaining the soil surface of the plant and that of the ground evenly.

Make sure to maintain the soil moisture evenly before and after completing transplantation by watering proportionately.

From Cuttings

Generally, you can start almost any method of propagation including cuttings in the spring.

1.) Using good quality, clean Garden shears cut off about four inches of stem from the top. Remove the leaves and other materials from the bottom two inches of the stem.

2.) Fill a pot with good quality potting medium. After dipping the cutting’s bottom end in the powdered rooting hormone, plant it in the prepared pot.

3.) By watering as needed, maintain the moisture of the potting medium.

4.) Within a few weeks’ time, the stem cuttings develop fresh leaves. This confirms the root formation.

5.) After that, transplant the rooted stems carefully. Maintain evenly the soil surface of the cuttings and that of the ground surface. Make sure not to damage the fragile roots.

6.) By watering regularly, maintain the moisture of the soil.

Caring Blue Balloon Flower Plants

Blue Balloon flower - Growing

Photo by  Qwertzy2 ( Wikimedia Commons) (CC BY-SA 3.0)

Generally, blue balloon flower (Platycodon Grandiflorus) plants are easy to grow, hardy, herbaceous perennials. Under ideal conditions, these plants can do well on their own. The established plants seldom require intervention.


By watering proportionately, maintain the moisture of the soil consistently. This is especially important for young plants. Mulching helps to retain the moisture.

Being hardy, the established plants can withstand short drought periods. However, maintaining soil moisture moderately can encourage their healthy thriving characteristics.


Normally, If the soil is rich, these plants do not require supplemental feeding. Excessive nitrogen can cause many problems in plants including legginess. So, avoid fertilizing especially if the soil is rich. However, if the soil is poor, amend it with slow-release, all-purpose fertilizer.

In summer, the plants spend most of their energy blooming. Hence, feeding them with a compost layer in Autumn can help to replenish energy.


During spring, cut off the stems by half using good quality shears and carefully avoid damaging the emerging shoots. This encourages more branching and promotes bushy, compact growth.

After the growing season (summer), remove all dead stems and other debris. This facilitates airflow around the plants.

If you skip pruning to a large part, the plants may grow leggy and require stalking.

To prevent self-sowing, simply deadhead the spend blooms. You can also cut off the stems having spent blooms before the seeds drop. After that, dry the harvested stems for collecting seeds.

However, the seeds may produce plants with different characteristics as most of the blue balloon flower plants are cultivated hybrid varieties.

Pests and Diseases

Normally, pests and diseases do not bother blue balloon flower (Platycodon Grandiflorus) plants. However, certain environments can invite problems.

Snugs and Snails

Under wet and moist environments, snugs and snails can infect these plants.

If they are less in number, you can just remove them with your hands. However, if they are more, you can sprinkle coffee grounds or broken eggshells around the plants. In addition to prevention, they also add nutrients to the soil.

You can also run the copper tape around or add a layer of bark, gravel, or wood chips to keep the snails and slugs away. Growing chickens, attracting birds Etc. are other efficient organic ways to deter most pests including snails and slugs.

Root rot

Mostly, this disease infects plants under wet and soggy conditions. The soil may not dry well in winters as it does in summers. Hence, facilitating proper drainage is essential to prevent this disease.

Powdery Mildew

Although powdery mildew mostly infects plants in warm and dry climates, it can thrive well in humid environments too. This fungus mostly lives on the surface cells rather than the inside of the plants.

The infected foliage develops ash-gray or white powdery mold on them. If left untreated, the infected part discolors, distorts, and finally drops off from plants.

Use sulfur fungicides or powdery mildew sprays to treat the infected plants. If the infection persists, remove and dispose of the infected balloon flower plants. Otherwise, the infection may spread quickly to other healthy plants.

Thinning the plants, periodical pruning Etc. can increase airflow. In addition to reducing soil wetness, this helps to prevent various diseases.

Cultivars of Blue Balloon Flower Plants

While shopping for these plants, you can find more cultivated varieties than true botanical species. We have listed some popular cultivated varieties of blue balloon flower plants below:

Astra Double

Being easy to care, the Astra series includes some of the popular dwarf, compact varieties. Due to their low – profile nature, these plants seldom require stalking.

Astra Double is a pest and disease resistant, hardy cultivar. It grows about 6 – 12 inches tall and about 6 – 9 inches wide. The lavender-blue blooms measure about three-inches across and have dual rows of petals.

Being compact and dwarf in nature, this plant is a perfect choice for border plantings and mixed beds

Astra Pink

Astra pink has similar growth and resilient characteristics to Astra double. Having single rows of petals, the pale pink flowers measure about three – inches across.

Being compact and dwarf in nature, Astra pink is well-suited for container gardens, border plantations, mixed beds, and rock garden arrangements.


Sentimental is another dwarf variety of blue balloon flower plants. This variety of plants grow about 6 -12 inches in height and spread about 12 -18 inches.

Having a single row of bluish-purple petals, the flowers measure about 3 inches across. The low-profile and wider spread makes them an excellent choice for border/edging plantations.

Fuji Blue

Being a tall cultivar, Fuji Blue may require stalking. This plant grows about 18 -24 inches in height and spreads about 12 – 18 inches.

Measuring about 2 – 2.5 inches across, the deep blue flowers have a single row of petals. This variety is well-suited for mid-bed arrangements.

Companion Plants of Blue Balloon Flower Plants

Blue Balloon flower - Companion plants

For companion plants, choose the ones that have similar water requirements and pose almost the same characteristics. Otherwise, there is a risk of one plant being over-saturated while the other being dehydrated.

Black-eyed Susan, Daylily, Lilyturf, Blazingstar, Bee balm Etc., are some of the best companion plants for blue balloon flower (Platycodon Grandiflorus) plants.


In Gardens

Photo by  VH-Halle ( Wikimedia Commons) (CC BY-SA 3.0)

The blue balloon flower (Platycodon Grandiflorus) plants are well suited for borders, edges, mixed beds, and also in container planting. The attractive features include the unique buds that resemble swollen balloons and the beautiful stary bluish-purple flowers

The dwarf varieties fit perfectly in rock gardens, containers, borders, edges, and spaces that demand compact profile plants.

The middle portion and rear portion of perennial beds are anchored by Medium-size varieties and taller species respectively.

In Medicine

For more than 2000 years, the people living in the far east have been consuming the fleshy roots of these plants for their health-related benefits.

Traditionally, the roots are used to treat fatigue, toothache, sore throats, coughs, and other ­respiratory disorders.

Killing liver fluke (internal parasite), the root extracts raised good cholesterol and lowered bad cholesterol in rats, in a recent study.

Photo by jetalone ( Wikimedia Commons) (CC BY 2.0)

The Japanese use the roots in their herbal extracts and serve the leaves in salads. The Koreans use the roots in their soups. They also pickle or preserve the roots in sugar.

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