Balloon flower (Platycodon grandiflorus) is one of those fun plants to grow in the garden with kids. Balloon flowers get their name from the unopened buds, which swell up prior to opening and resemble little hot-air balloons. Kids are fascinated by these plants and will typically pop them for sport by squeezing the sides, making them burst open with a soft, popping sound. Growing balloon flowers with children can be quite fun. The opened flowers resemble those of bellflowers, their kissing cousin. While most often deep blue or purple, white and pink varieties are also available. Depending where you are, the balloon flower may also be known as Chinese or Japanese bellflower.
I. Appearance and Characteristics
Platycodon grandiflorus (from Ancient Greek πλατύς “wide” and κώδων “bell”) is a species of herbaceous flowering perennial plant of the family Campanulaceae, and the only member of the genus Platycodon. It is native to East Asia (China, Korea, Japan, and the Russian Far East). It is commonly known as balloon flower (referring to the balloon-shaped flower buds), Chinese bellflower, or platycodon.
Growing to 60 cm (24 in) tall by 30 cm (12 in) wide, it is an herbaceous perennial with dark green leaves and blue flowers in late summer. A notable feature of the plant is the flower bud, which swells like a balloon before fully opening. The five petals are fused together into a bell shape at the base, like its relatives, the campanulas.
Flowers bloom purple or white in July and August, with one or several running upward at the end of the circle. The flower crown is divided into five branches in the shape of an open bell.
This plant is hardy down to −40 °C (−40 °F), and can be cultivated in USDA zones 3A to 9b.
It dies down completely in winter, reappearing in late spring and flowering in summer. However, plants are widely available from nurseries in full flower from April onwards.
Though the species has blue flowers, there are varieties with white, pink, and purple blooms. In Korea, white flowers are more common. This plant, together with its cultivars ‘Apoyama group’ and ‘Mariesii’, have gained the Royal Horticultural Society’s Award of Garden Merit.
II. How to Grow and Care
Sunlight
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.
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.
Watering
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.
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.
Fertilizing
When the soil is rich, balloon flower doesn’t require any additional fertilizer, although an application of compost in the fall invigorates the plants. In areas where the soil is poor, apply a balanced, slow-release fertilizer in the spring, following the product instructions.
Planting Instructions
Start seeds indoors in seed-starting mix six to eight weeks before the last frost date in spring for blooms the first year, or directly sow them on the surface of a prepared garden bed after the last frost date for blooms the second year. Either way, don’t cover the seeds; they require light to germinate. Keep the soil or growing medium moist but not soggy.
Plant nursery starts in the garden in early spring for blooms the first year, or plant them later in the year for blooms the second year. Dig a hole in the garden the same size as the root ball. Remove the balloon flower from its container gently, being careful not to damage the roots, and set it in the hole at the same depth it was in its container. Firm the soil around it and water the plant.
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.
Propagation
Gardeners can propagate their balloon flower plants in three ways: by collecting seed from a mature plant in the fall, from stem cuttings, and by division. Propagating with seed is a simple process. Working with stem cuttings is not much more difficult, but propagating by divisions is challenging and has a high failure rate due to potential root damage.
- Seed
After a bloom dies, look for the brown pod at the end of the stem. Let it dry on the plant and then cut the stem and pod off the plant and place them in a paper bag. Pop open the pod to release hundreds of tiny seeds. In spring, after all chance of frost is past, dig compost into a garden bed in an area that receives full sun to part sun. Sprinkle the seeds on top of the bed, but don’t cover them. Water the seeds and keep the soil moist until they germinate in about two weeks. Continue to keep the soil moist as the seedlings grow. If starting seeds indoors, sow them six to eight weeks before the last spring frost and transplant them when the weather warms.
- Stem Cuttings
In the spring, take 4-inch cuttings from soft, growing stem tips. Remove the foliage from the bottom half of the cuttings. Dip the bottom end of the cuttings in rooting hormone and plant them in individual pots filled with a sterile planting mix or seed-starting medium. Cover each pot and plant with a clear plastic bag, and place the pots in a bright light (not full sun) location, keeping the soil moist but not soggy until the cuttings root. New leaf growth indicates the cuttings have rooted. Transplant the rooted plants to the garden, being careful not to disturb the roots.
- Division
The long taproot of balloon flower complicates propagation by division. Divide the plant in the spring while it is still small. Dig a circle around the plant that is at least 12 inches away from the main clump of flowers to avoid damaging the root system and lift it from the ground. Using a sharp knife, cut down the middle of the taproot and plant, making sure each half of the taproot has at least one growth node. Replant the two halves immediately.
Potting and Repotting
Balloon flower grows well in containers as long as the container is deep enough to accommodate the plant’s long taproot; 10-12 inches is usually sufficient. As for width, the container should be at least 2 inches wider than the anticipated size of the mature plant. Good drainage is a necessity.
Balloon flower doesn’t like to be transplanted. When it outgrows its current container, wait until the plant is actively growing before repotting, taking care not to damage the taproot.
Pests and Diseases
Balloon flowers generally attract slugs and snails, as do many other outdoor bloomers, which can be coaxed off the plants with bait. However, the plant may become afflicted with crown rot, root rot, botrytis gray mold, powdery mildew, or fungal leaf spot. Crown and root rot may cause plants to die over the winter. Leaves presenting powdery spots, mottling, or blotching can usually be treated with a fungicide. Quickly discard plants with gray mold so it doesn’t spread, then use a preventative fungicide on remaining plants.
III. Uses and Benefits
- Ornamental uses
Gardeners like balloon flower for its excellent cold hardiness and tolerance for less-rich soils. Often grown in clumps to maximise the impact of its striking flowers, this plant is ideal for wide borders, rock gardens and containers, especially alongside Lavender, Catmint, or Coreopsis.
- Medicinal uses
The extracts and purified platycoside compounds (saponins) from the roots of Platycodon grandiflorum may exhibit neuroprotective, antimicrobial, anti-inflammatory, anti-cancer, anti-allergy, improved insulin resistance, and cholesterol-lowering properties. Evidence for these potential effects was mainly observed in vitro, with the exception of cholesterol lowering effects documented in vitro and in rats. The lack of efficacy and limited safety data in humans, however, necessitate further research.
China
The Chinese bellflower (called 桔梗 in Chinese) is also used in traditional Chinese medicine.
In China, they are used as a cough suppressant and expectorant for common colds, cough, sore throat, tonsillitis, and chest congestion.
Korea
In Korea, the roots are commonly used for treating bronchitis, asthma, tuberculosis, diabetes, and other inflammatory diseases.
- Culinary uses
In Korea, the plant as well as its root are referred to as doraji (도라지). The root, fresh or dried, is one of the most common namul vegetables. It is also one of the most frequent ingredients in bibimbap. Sometimes, rice is cooked with balloon flower root to make doraji-bap. Preparation of the root always involves soaking and washing (usually rubbing it with coarse sea salt and rinsing it multiple times), which gets rid of the bitter taste.
The root is also used to make desserts, such as doraji-jeonggwa. Syrup made from the root, called doraji-cheong (balloon flower root honey), can be used to make doraji-cha (balloon flower root tea). The root can be used to infuse liquor called doraji-sul, typically using distilled soju or other unflavored hard alcohol that has an ABV higher than 30% as a base.
In addition, other ingredients include calcium, fiber, iron, minerals, proteins and vitamins.
- Cosmetic uses
IV. Types of Balloon Flowers
There are several popular varieties of balloon flowers, including:
- Platycodon grandiflorus Astra series: This type grows double flowers with 10 petals in blue, pink, or white. They’re an ideal choice to start from seeds.
- P. grandiflorus Fuji series: This is the most commonly sold variety, 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 stay in their puffy pillow stage even after blooming.
- P. ‘Sentimental Blue’: This dwarf variety grows about 6 inches tall with lots of 1- to 2-inch purple flowers.
