Balloon Flower Guide: How to Grow Balloon Flowers

The balloon flower (Platycodon grandiflorus), also known as the Chinese bellflower, is an herbaceous perennial plant that is a member of the Campanulaceae family. Herbaceous plants are vascular plants that do not have woody stems above ground, making their stems soft. Balloon plants bloom time lasts the length of summer.

Balloon flowers are called such because the buds inflate and puff into a balloon-like shape before they bloom outward. Once opened, the balloon plant appears in a more traditional, star-shaped form. This star shape is unique within the bellflower family as the other varieties resemble bells.

Balloon flowers, which have a low maintenance disposition, are native to eastern Russia, China, Japan, and Korea. They have gained popularity in the US because they are hardy, easy to grow, and bring vibrant colors to many garden styles—including rock gardens.

They thrive in organically rich and moderately moist soil that’s well-drained. While balloon plant sizes vary, the species in its native homes can exceed 3 feet tall and 18 inches wide at maturity.

These flower buds come in purple, blue, white, and pink, making them a beautiful addition to a garden or vase as cut flowers. Balloon flowers also grow to different sizes depending on the cultivar.

1. 1. ‘Astra Double’: A dwarf variety that grows up to 6 to 12 inches tall and 6 to 9 inches wide. The flowers have a 3-inch diameter and typically have lavender-blue petals. They are pest and disease-resistant and grow particularly strong with regular deadheading.
2. 2. ‘Astra Pink’: This option has the same growth dimensions at maturity as the Astra Double, while developing a pale pink, single row of petals.
3. 3. ‘Fuji Blue’: This variety has a little more height than the others, growing up to 24 inches tall and 12 to 18 inches wide. The flowers are slightly smaller at 2 to 2.5 inches across, with a single row of deep blue petals. While the other shorter heights make them great for planting along the outer edge of beds, this taller bloom works best mid-bed and may need staking for support.
4. 4. ‘Double Blue’: This variation features two full layers of star-shaped blue petals, which inspired the "double blue" name.
5. 5. ‘Sentimental’: This variety spreads out a little more than the others, with mature heights at 6 to 12 inches tall and 12 to 18 inches wide. The 3-inch diameter flowers feature a single row of blue petals. The lower profile makes sentimental blues great for border edging.

There are several ways to begin your balloon flower plant garden, though the best option is starting indoors from seeds as it puts the least amount of stress on the roots.

• From seeds: Plant them indoors with seeds on the surface so they can absorb maximum sunlight. When they develop leaves, you can expose them to a few hours of sun for three to five days. Once they have adjusted, you can plant them outside, without covering them.
• From a nursery: In the first year, move your transplants to your garden in early spring. If you plant during another season, they may not bloom until the second year. Dig a hole the same as a seed start, keeping pot soil and ground soil level with one another. Gently remove the plant from the container without disrupting the roots and planting, maintaining even moisture throughout.
• From cuttings: In the spring, cut about 4 inches of a stem and put the soft cuttings in water until they develop roots. Dip the stem in powdered root hormone and place it into a container of potting soil, maintaining moisture without overwatering. Once leaves appear, transplant the rooted stem to the garden, planting it at the same depth as the container in which it was growing.

Balloon flowers are easy to grow, but especially so when starting from seeds:

1. 1. Start your seeds indoors: Plant seedlings approximately 4-6 weeks before the last spring frost. Keep the seeds on the surface without covering them so that they can absorb all of the sunlight they need while they also receive nutrients from the moist soil.
2. 2. Harden off: Once the seedlings develop two sets of true leaves and temperatures have risen outside, it’s time to start hardening off, which is the process of preparing them to move outside. Simply place them outside in the sun for a few hours every day for three to five days.
3. 3. Move the plants outside: Once your plants have adjusted, take them outdoors while being mindful of the fragile roots. Dig a hole the same depth and width as the root ball, keeping the soil surface even with the ground soil surface.
4. 4. Moisten the soil: Sprinkle seedlings throughout the planting area without covering them.

Balloon flowers are vigorous self-sowers, meaning they drop pods, capsules, or seeds, quickly germinating in the soil. However, balloon flowers’ fragile roots make transplanting and propagation challenging. Therefore, growing from seeds and allowing the flowers to self-sow are the best starting points.

1. 1. Blue Flowers grow best in full sun or partial shade after late spring planting. They are hardiness zones three to eight, thriving from 60–80 degrees. If growing in a hotter climate, balloon flowers will likely need afternoon shade during the hotter parts of the day.
   
2. 2. Take care of fragile roots. If transplanting, use more balloon flowers than needed as many won’t survive the move due to their fragile roots. The propagation method of division, where the plant is broken up while keeping the crown and roots intact, is not recommended as it inevitably causes root damage for this variety.
3. 3. Don’t fertilize balloon flowers. Organically-rich soil with a pH between 5.5 and 7.5 provides plenty of nutrition, while too much nitrogen from fertilizer can cause leggy stems. If soil tests show too much acidity, add lime, and to add acidity, use coffee grounds.
4. 4. Be cautious with water. Once balloon flowers are established in a garden, they require little supplemental water thanks to their deep taproots. At most, they should be watered once a week. Always avoid standing water.
5. 5. Dwarf varieties are best grown in containers. Be sure to choose pots at least 2 inches wider than the width of the plants at full maturity and a foot deep with excellent drainage to ensure room for the taproots. Containers dry out quicker than ground soil and may require more watering to maintain uniform moisture.
6. 6. Fill your garden with complementary plants. Other flowers that grow well alongside balloon plants are Bee Balm, Black-Eyed Susan, Blazing Star, Daylily, and Lilyturf.

Balloon flowers are prolific self-sowers and can sometimes be invasive. To limit the potential of overgrowth, practice deadheading bulbs throughout the season, removing all stems after blooming ceases. Another option is to give an active self-sower space to grow and reseed.
To ensure your plants grow tall and not wide, cut leggy stems in half in late spring to encourage branching. At the end of summer when blooming is done, cut the dead stems to the ground. Attaching stakes to support the stems also helps them to grow upright.
The late summer bloomers are deer-resistant, disease-resistant, and mostly pest-resistant. However, gardens with more moisture could attract slugs and snails. These pests can be deterred by placing a small bowl of beer nearby. Mulch is also a great option to help absorb excessive moisture.
These flowers are not toxic to humans or animals. In fact, the edible roots have long been used in herbal remedies, providing anti-inflammatory, antitussive, and digestive benefits.

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