The first thing that will catch your eye on balloon flowers (Platycodon grandiflorus) is the shape of the buds. They puff up like tiny balloons, then burst open, forming blue-violet, bell-shaped flowers that resemble the bellflowers they’re related to. While balloon flower is best known for the summertime blue it adds to gardens, there are also lovely soft pink and pure white cultivars that, like the blue species, bring colorful, long-lasting blooms to gardens.
Common name: Balloon flower
Botanical name: Platycodon grandiflorus
Plant type: Herbaceous perennial
Height: 8 to 36 inches, varying by cultivar
Zones: 3 to 9, varying by cultivar
Sun: Full sun to part shade
Soil: Light, well-drained, loamy soil
Fertilizing: None required if soil is adequate.
Pruning: Deadhead spent flowers to encourage more flowering. Cut back foliage and flowers after first hard frost.
Mulch: To protect roots through winter, add a few inches of organic mulch around plants after the ground is frozen.
- ‘Astra Pink’ (pictured) has a compact form 8 to 10 inches tall. Good for cut flowers. Zones 3 to 8.
- ‘Double Blue’ has double blue blooms. Grows 15 to 20 inches tall. Zones 4 to 9.
- f. albus has white flowers. Grows 24 inches tall. Zones 4 to 9.
- ‘Fuju White’ has pure white flowers on 24-inch stems. Zones 3 to 8.
- ‘Komachi’ has blue buds that stay closed and balloon-shaped. Grows 12 to 18 inches tall. Zones 3 to 8.
- ‘Plenum’ has semi-double, light blue flowers. Grows 24 inches tall. Zones 4 to 9.
- ‘Sentimental Blue’ has 3-inch-wide, upward-facing blue flowers. A dwarf cultivar, it grows 6 to 12 inches tall. Zones 3 to 8.
- Balloon flowers emerge slowly in the spring, so mark their location to avoid damaging the crown or accidentally planting other perennials too close.
- Plant with Shasta daisy (Leucanthemum superbum), daylilies (Hemerocallis), baby’s breath (Gypsophila paniculata), asters, and Coreopsis verticillata ‘Moonbeam’.
- Before placing balloon flowers in a cut-flower arrangement, sear bottoms of the milky stems to seal them.
- Taller balloon flowers often fall over if not staked, so choose dwarf cultivars if you prefer a tidy look and don’t want to stake flowers.
- Stake taller plants shortly after they emerge in spring. Later staking may cause stalks to break.
- Slugs and snails occur, but rarely.
- Sow seeds in spring. They need light for germination.
- Roots are difficult to divide and transplant, but the best time is early summer when new leaf shoots are a couple inches tall.
All in the family
The Campanulaceae family includes cardinal flower (Lobelia cardinalis), swamp lobelia (L. paludosa), and blue cardinal flower (L. siphilitica). It also encompasses 300 bellflowers such as Campanula [MP1] carpatica and its cultivars ‘Blue Clips’, ‘Jewel’, and ‘Bressingham White’; clustered bellflower (C. glomerata) and its cultivars ‘Joan Elliott’ and ‘Crown of Snow’; and harebell (C. rotundifolia).
Text by Mary Pestel, photo courtesy of Walters Gardens, www.perennialresource.com.