Balloon flowers (Platycodon grandiflorus) are often grown for their whimsical flower buds, but this plant is one tough cookie. The balloon flower is part of the easy growing Bellflower/Campanula family, and you will notice the resemblance right away.
The botanical name means "broad bell," but the open flower is really more of a star shape. However, it's the puffy bud that intrigues gardeners and entices them to grow this plant and that gives it its common name of "balloon flower.”
Balloon flowers are long-lived perennials that rarely need dividing and are deer-resistant.
|Botanical Name||Platycodon grandiflorus|
|Common Name||Balloon flower, Chinese bellwflower, Japanese bellflower|
|Plant Type||Perennial flowers|
|Mature Size||Varies; most grow to 1 to 2 feet tall and 1 foot wide|
|Sun Exposure||Full sun, partial shade|
|Soil Type||Loamy, well-drained|
|Soil pH||5.8 to 6.8|
|Flower Color||Blue, white, pink|
|Hardiness Zones||3 to 9|
|Native Area||China, Korea, Japan, Russia|
How to Grow Balloon Flowers
You can start with plants or seed, although seed grown plants will not bloom their first year. Balloon flower seeds will require stratification and are a good choice for winter sowing. If you leave the seed pods on at the end of the season, you will probably get a few volunteer plants the following spring.
Start seed indoors in early spring, and gently press the seed on top of moist soil. They need light to germinate, so do not cover the seed with soil. Seed should germinate within two to three weeks. Move seedlings into larger pots and slowly harden off, before transplanting outdoors. The taller varieties of balloon flower can become a bit floppy, but rather than staking them, just plant them in large drifts and let them support each other.
Balloon flowers are pest- and disease-resistant, though root rot can occur in soil that's too wet. Keep an eye out for slugs and snails.
You will get the most flowers if you plant balloon flowers in full sun, however, they will be fine in partial shade, especially if the shade comes in the afternoon.
Balloon flowers prefer a slightly acidic soil pH in the 5.8 to 6.8 range. It should be well-drained and slightly loamy.
Once established, balloon flowers won't need a lot of supplemental watering. They can handle short periods of drought.
Temperature and humidity
Ballon flowers enjoy 60 degrees to 80 degrees Fahrenheit but can also withstand higher temperatures if they have some shade in the afternoon. They are also tolerant of humidity.
Balloon flowers are not heavy feeders, but a top dressing with compost in the fall will help them replenish the energy they expended blooming. It's also good to add some granular organic fertilizer to the whole bed, in the spring.
You can try making divisions, but the root system is dense and chunky, with a long taproot and doesn't really like being disturbed. To propagate by division, instead of digging up the whole plant, slice a piece of the plant off with a sharp knife. Make sure you get at least a ½ inch piece of the root. Pot it up and keep it moist. If you plan on trying to divide, do it early in the season, when the plants are small, and expect them to take a season or two to start blooming again.
Varieties of Balloon Flowers
This is one of those classic plants that is often sold as an unnamed variety. Don't be afraid to purchase plants without pedigrees; they will grow fine and look lovely. Some pedigreed varieties include:
- Platycodon grandiflorus Astra series: The flowers are double with 10 petals in blue, pink, or white. It's 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 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.
When you're considering companion plants, keep in mind that balloon flowers won't really start flowering until mid- to late summer but will continue to flower into fall. The blue varieties go especially well with the pale yellows of lilies, Ratibida, and yarrow. Because the pink and white varieties can be paler than many fall blooming flowers, give extra thought to where you tuck them. They look great next to ornamental grasses and spiky plants, such as Persicaria, Celosia, and Liatris. They also shine next to bold colors like Cosmos "Cosmic Orange."
For stockier plants, you can pinch them back when they are about 6 inches tall. Deadheading will keep the plants 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.