Balloon Flower: Growing The Chinese Bellflower

The Japanese or Chinese bellflower, also called the balloon flower, is a gorgeous and vibrant pop of color in the garden. We offer care tips!

Balloon flower

The balloon flower is a popular plant. Lush green foliage sets off massive five-pointed flowers that open up like stars from puffy, balloon-like buds, making the perfect edging plant or container garden.

But how does one grow these Asian plants to their utmost potential? We’re going to explore growing balloon flowers in detail, and when you’re finished reading, you’ll know exactly what you need to do to make these gorgeous plants thrive.

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Balloon Flower Overview

Balloon flower in bloom
Balloon flowers ballooning. Source: santafeegret
Common NameBalloon flower, platycodon, Japanese bellflower, Chinese bellflower, kikyo, doraji
Scientific NamePlatycodon grandiflorus
FamilyCampanulaceae
LightFull sun to partial shade (partial shade in very hot locations)
WaterPrefers deep, consistent moisture but does not like boggy conditions
Temperature60-80 degree temperatures preferred, can survive hotter if given shade midday
HumidityTolerant of humidity
SoilWell-draining loamy soil with compost mixed through it for moisture retention
FertilizerSlow-release nitrogen fertilizer prior to planting
PestsSnails and slugs
DiseasesIt may be susceptible to root rot if the soil is too soggy but otherwise tends to be disease-resistant

All About Balloon Flower

Platycodon grandiflorus in bloom
Platycodon grandiflorus in bloom. Source: Jim the Photographer

The balloon flower originates in eastern Asia, as evidenced by names such as kikyo (Japanese) or doraji (Korean). Also referred to as the Chinese bellflower, the Japanese bellflower, or the platycodon, its name comes from the balloon-like buds that puff up like tiny balloons before they open.

These beautiful flowers can grow from six inches to up to three feet in height. Some of the more recently-developed cultivars have specifically been bred for their dwarf size, making them much easier to plant as an ornamental.

This plant produces flowers in mid to late summer. With blue, pink, or white balloon flowers that reach 2-3 inches wide, they are an excellent attractor for birds or other wildlife. It’s such a popular plant that many cultivars have been awarded the Royal Horticultural Society’s Award of Garden Merit.

In some parts of Asia, Platycodon grandiflorus is grown as an edible plant. The roots of balloon flowers are widely used as edible root vegetables, and they are referred to as doraji (Korean). Balloon flowers are also believed to have medicinal properties and are used in China and Korea for various medical conditions.

Amongst the Japanese, the bellflower is considered one of the seven autumn flowers renowned for its beauty. The kikyo flower shape is also used as a kamon or crest for some Japanese clans.

Caring For Balloon Flower

Unopened but ballooned flowers behind an open flower
Unopened but “ballooned” flowers behind an open blossom. Source: Jim the Photographer

For the most part, caring for a balloon flower plant is a very simple process. Balloon flowers are very tolerant of many weather conditions and can be grown throughout most of the United States and in many other countries. But what are the best conditions for your plant? Let’s go over that.

Light & Temperature

Balloon flowers prefer locations with cool summers but can be grown in hotter conditions if careful attention is paid to the plants’ needs. While in cooler climates it prefers full sun, hotter locations should opt for partial sun conditions.

Platycodons grow easily in growing zones 3-8 in the United States. Balloon flowers are also commonly grown in zone 9 but can have some difficulty in the peak of summer.

When you plant balloon flowers in areas with winter frost or freeze conditions, provide mulch in the fall to at least 2-3″ in depth over the plant’s base. This keeps the plant’s crown protected from the colder conditions and allows it to overwinter well.

Water & Humidity

Closeup image of balloon flower showing petal veining
A closeup of the center of a balloon flower showing the petal veining. Source: dspindle

Watering your balloon flower plants can be a bit tricky. That’s because balloon flowers are very thirsty and require lots of moisture. However, they don’t like boggy conditions or soggy soil, so you’ll have to be careful.

When you grow balloon flowers, using soaker hoses for irrigation may be of great benefit to ensure there is moist soil. The balloon flower has a deep taproot, and doing slow, deep irrigation should keep you from over-watering while still ensuring that they have enough for their thirst.

Soil

Due to their desire for moist but not soggy soil, having an organically rich soil base when you grow balloon flowers is a good idea. The plant matter in the soil will hold some moisture while the excess drains off easily. I recommend opting for a well-draining loamy soil with some compost worked through.

Your balloon flower can tolerate sandier soils as well and is often grown in a rock garden environment in portions of its native east Asia. Balloon flowers can also grow easily in containers or as bedding/border plants, where soil conditions are typically very well-draining. Rock gardens are also great settings for these purple-blue flowers.

Not picky on soil acidity, balloon flower plants will accept soils ranging from 5.6 to 7.5 pH. Aiming for the neutral ground in the middle is usually your easiest bet to ensure it doesn’t go too heavily alkaline or acidic.

Fertilizer

Platycodon grandiflorus does not really need heavy fertilization as long as it’s got lots of organic matter in its soil. We recommend working in a slow-release nitrogen fertilizer directly into the soil before planting balloon flowers, but otherwise, they should be fine for the rest of the first year.

In subsequent years, you can scratch some nitrogen fertilizer into the upper portions of the soil surface around your balloon flowers or add a layer of nitrogen-rich compost around the plant’s base and water it in well. It isn’t a heavy feeder, so avoid over-fertilizing.

Propagation

Balloon flowers can be propagated most easily from seed but can be propagated by cuttings or by division as well.

However, I honestly recommend planting balloon flowers from seed. Cuttings are extremely slow to develop roots and can fail before the roots ever fully form. Division is tricky because the platycodon root system is fragile and prone to injury.

In addition, balloon flowers don’t like being disturbed once they’ve become established in a location, so while division is possible, it’s something we truly don’t recommend. You’re as likely to risk severe damage to your plant as you are to propagate more.

To plant balloon flower seeds, direct sow them in the garden plot in early spring.

Repotting

As I just mentioned, your balloon flower plants don’t really like to move once they’re established. The balloon plant develops an extremely long taproot with lots of fragile tendrils extending outward from it. If possible, plant your Chinese bell flower plant in a permanent location initially.

However, if it’s absolutely necessary to repot or transplant your balloon flowers, be extremely careful with their root system to ensure you have balloon-like buds next year. Try not to pull much of their existing soil away from the root structure, instead opting to transplant both the plant and its soil.

Work very slowly and cautiously to ensure that you do not slice through the wide portion of the taproot of your balloon flowers or damage too many of their tendrils, and make sure that each plant’s crown is planted at the same depth it was originally planted.

Pruning

Most of your pruning duties for your balloon flower will focus on deadheading spent flowers to prevent the prolific spreading of balloon flower seeds. Removing the spent flowers can prolong its blooming period significantly, sometimes well into the fall months.

Once fall arrives, you may wish to leave old plant stems of balloon flowers in place throughout the winter. This helps you to identify the locations of the plant, as they’re slow to regrow in the spring. Once new growth begins, you can trim off the old tall stems and allow the plant to produce new shoots.

If you have one of the taller varieties of balloon flowers, consider cutting back the plant’s tall stems by half in May to reduce your plant’s size and avoid staking or other support structures. This should be done prior to blooming, and while it’ll slow the flower show, it won’t grow as tall and thus won’t flop over.

Balloon Flower Problems

Pollen on a balloon flower
Pollen from the side of the flower collected at the center. Source: tanakawho

Your balloon flower plant should have very few problems. These are very easy to care for! However, what few you might encounter are laid out for you below.

Growing Problems

Taller varieties of balloon flower may start to flop over without adequate support. Ring support or stakes may be necessary to maintain an upright position for your balloon flowers. Alternately, prune as indicated above to encourage shorter growth at the time of flowering.

Your platycodon may be slow to emerge in the springtime. Don’t expect an immediate flush of new growth and tall stems once the final day of winter has passed, as your plant will still be dormant. It may take a couple of weeks in slightly-warmer spring weather before it comes back to life.

Pests

Very few pests tend to bother balloon flowers. The only problems tend to come from snails and slugs, which find young foliage to be absolutely delicious.

To protect your platycodon plants from the slug and snail army, be sure to use organic bait to draw them away from the planting area. You can actually create a ring of bait around plants if you need to, just to keep damage away!

While deer may nibble on your plant from time to time, it is generally considered to be deer-resistant. They don’t seem to like the taste of anything other than the newest young leaves. Once your plant’s leaves mature, the deer will move on.

Diseases

Diseases are not common among Japanese bell flower growers. In fact, the only thing which may be a concern is root rot if your soil is overly wet for too long. This generally is not a problem through the winter and early spring but may become an issue during summertime.

Because of this, it’s important to be sure your soil’s moist but not soggy. Use well-draining and organic-rich soil that can hold some moisture within to supply your thirsty balloon flower’s beverage needs but that won’t hold excess water captive.

Frequently Asked Questions

Platycodon grandiflorus flowers
Platycodon grandiflorus flowers in bloom. Source: jeancflanagan

Q: Is there a difference between Platycodon grandiflorus and Platycodon grandiflorum?

A: These are both terms used to refer to the same balloon flower plants. Its actual botanical name is Platycodon grandiflorus. However, many websites out there refer to Platycodon grandiflorum when discussing doraji root, and it’s become a bit confusing.

It is quite possible that the Korean botanical name for this plant is Platycodon grandiflorum, as that name shows up in medicinal studies from the region. However, the names are interchangeable, as they refer to the same exact species of plant.

Q: How fast do balloon flowers grow?

A: About 2 to 3 months. After they are direct seeded in early spring, balloon flowers bloom in mid to late summer.

Q: Does the balloon flower spread?

A: The balloon plant spreads via the seeds that spread readily after the flowers fade and pods open.

Q: How tall does balloon flower grow?

A: Depending on whether or not you’re growing a dwarf variety, they’ll grow to 6 inches to 1 foot tall. They spread roughly one foot per plant as well.

Q: Will balloon flowers survive winter?

A: While they won’t technically survive above ground, protected and mulched roots will grow new shoots in spring. The plant also self-seeds, adding to the growth that occurs in spring.

Q: Do balloon flowers rebloom?

A: If you cut them back as they reach the peak of their bloom, they’ll push out one more flush of flowers.

Q: Should I cut back balloon flowers?

You can cut them back as they emerge in spring to keep them from getting too tall and floppy.

Q: Is balloon flower toxic to dogs?

The basal leaves and roots may be slightly toxic, but balloon flowers are typically recommended as a replacement for more toxic flowers that can be grown in a perennial garden.

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