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How to Grow Balloon Flower — Platycodon

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Platycodon–commonly called balloon flower–is a perennial that bears mostly purple-blue flowers opening from balloon-like buds from spring through early fall. The inflated flower buds that look like balloons split open into broad, shallow, bell-shaped flowers.

A single species comprises the genus Platycodon, however, there are several cultivars; some may bear white or pink flowers. Flowers are borne at the end of slender, leafy stems. There are dwarf cultivars and some with semi-double flowers.

Platycodon are clump-forming with lance-shaped bluish-green leaves that are toothed. Leaves turn almost clear yellow in fall. Plants grow from 12 to 24 inches (30-61cm) tall.

Platycodon thrives best in deep, well-drained, sandy loam soil. They are a good choice for flower borders and rock gardens.

Platycodon is easily grown from seed sown in early spring or propagated by division also in spring.

Balloon flower, Platycodon grandiflora
Balloon flower, Platycodon grandiflora

Get to know Platycodon

  • Plant type: Herbaceous perennial
  • Growing Zones and range: Zones 3 to 8
  • Hardiness: Hardy to -35°F (-37°C) plants die back completely in fall or winter
  • Height and width: 12 to 24 inches (30-61cm) tall and wide
  • Foliage: Ovate to ovate-lance-shaped, toothed, bluish green leaves
  • Flowers: Bell-shaped flowers; buds swell into puffy “balloons’ before opening into rounded bells
  • Flower colors: Blue, pink, white
  • Bloom time: Midsummer to fall
  • Uses: Mixed flower garden beds, borders, cottage gardens, rock gardens
  • Common name: Balloon flower, Chinese bellflower
  • Botanical name: Platycodon grandiflorus
  • Family name: Campanulaceae
  • Origin: Meadows in Eastern Asia

Where to plant Platycodon

  • Plant Platycodon in full sun in Zones 3-6; plant in light afternoon shade in Zones 7-8. Plants growing in full sun are likely to need staking.
  • Grow Platycodon in humus-rich, deep, well-drained soil.
  • Platycodon prefers a soil pH of 5.5 to 7.5.

Platycodon uses and companions

  • Use Platycodon at the front of an herbaceous border or in a rock garden.
  • Platycodon is a good addition to a midsummer border.
  • Platycodon are good cut flowers.
  • Good garden companions for Platycodon include Astilbe, Campanula, Heuchera, Hosta, Malva.
Balloon flower, Platycodon grandiflorus astra
Balloon flower, Platycodon grandiflorus astra

When to plant Platycodon

  • Set Platycodon in the garden in spring or fall.
  • Sow seeds indoors a few weeks before the last frost in spring; sow seeds in the garden after the last frost in spring.
  • Container-grown plants are best set in the garden in spring or autumn, not in the summer heat.

Planting and spacing Platycodon

  • Platycodon can be started indoors in six-packs or individual pots filled with clean seed-starting mix. Sow seeds 1/8 inch deep.
  • Sow seeds in the garden in finely prepared soil; sow seeds 1/8 inch deep. Sow seeds where plants will grow; Platycodon does not like being moved once established.
  • Space balloon flowers 12 to 24 inches (30-61cm) apart.
Platycodon grandiflorus
Platycodon grandiflorus

How to water and feed Platycodon

  • Platycodon wants ample moisture; keep the soil evenly moist.
  • Fertilize Platycodon occasionally with an all-purpose fertilizer or work slow-release fertilizer into the soil in spring.

Platycodon care

  • Mulch around Platycodon to keep the soil evenly moist.
  • Tall Platycodon cultivars require staking so they do not flop over.
  • Trim spent flowers to encourage new blooms.
  • Cut back plants by one-third after flowering to promote new growth.
  • Mark plant locations in fall before plants go dormant; plants will reemerge in spring.
  • Platycodon are commonly pest free.

Platycodon pests and diseases

  • Platycodon are usually trouble free, but may be attacked by slugs and snails.
Balloon flower, Platycodon grandiflorus
Balloon flower, Platycodon grandiflorus

Platycodon propagation

  • Platycodon can be propagated by seed, division, or cuttings.
  • Platycodon seeds will germinate in 10 to 15 days at 65° to 75°F (18°-24°C).
  • Most Platycodon cultivars grow true from seed, and plants tend to self-sow.
  • Platycodon seldom need division apart from propagation. Divide plants in spring or early fall and replant divisions immediately.
  • Rooted shoots sometimes appear at the base of clumps; they can be separated from the clump and replanted.
  • Softwood or semi-ripe cuttings can be rooted in early summer.

Platycodon species and cultivars to grow

  • Platycodon grandiflorus. Long-lived perennial grows to 24 inches (61cm) tall and bears 2-inch wide blue-violet, lilac-blue, pink, or white flowers from early summer to mid-summer. Subspecies ‘Mariesii’ bears purple-blue flowers; ‘Sentimental Blue’ has lilac-blue flowers; ‘Shell Pink bears pale pink flowers; ‘Double Blue’ bears double lilac-blue flowers; Fuji Series have white, pink, and blue flowers.

Written by Stephen Albert

Stephen Albert is a horticulturist, master gardener, and certified nurseryman who has taught at the University of California for more than 25 years. He holds graduate degrees from the University of California and the University of Iowa. His books include Vegetable Garden Grower’s Guide, Vegetable Garden Almanac & Planner, Tomato Grower’s Answer Book, and Kitchen Garden Grower’s Guide. His Vegetable Garden Grower’s Masterclass is available online. has more than 10 million visitors each year.

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