Balloon Flowers: How to Plant, Grow, and Care For Platycodon Grandiflorus
Are you looking to plant balloon flowers in your garden? These perennials feature stunning, large flowers atop short or tall stems that will captivate any garden guests. Take a look at this article for absolutely everything you need to know to successfully grow these plants in your own backyard.
When it comes to interesting flowering plants, balloon flowers are one of the first to come to mind. These adorable perennials are named after their blooms, with petals that expand to form a balloon shape before opening up into a star-shaped beauty. The petals are lined with darker veins that add even more interest to the stunning flowers.
These plants are incredibly low-maintenance and will require little attention from you after planting. When planted en masse, they create waves of color in pots or throughout your garden beds. They are also ideal for mixed perennial plantings, complementing other flowers while standing out in their own right.
There is little excuse not to plant one of these stunning plants this season. And, with several cultivars to choose from, you’re bound to find the right one for you.
Balloon Flower Plant Overview
Plant Type Perennial
Species Platycodon grandiflorus
Native Area Asia
Hardiness Zone USDA 3-8
Exposure Full Sun to Partial Shade
Maturity Date 1 Year
Growth Rate Fast
Plant Spacing 20 inches
Planting Depth 10 inches
Height 12-30 inches
Heat Tolerance Moderate-High
Watering Requirements Low
Pests Snails, Slugs
Diseases Crown rot, Root Rot, Pwdery Mildew
Soil Type Loamy, Well-draining
Plant With Dahlias, Salvias, Bee Balm
Don’t Plant With Water-dependent Plants
Balloon flowers are part of the Campanulaceae family, known as Platycodon grandifloras. They are the only member of the Platycodon genus, giving them the same common name. They are also known as Chinese bellflowers due to their country of origin.
These plants may have originated in Asia, but they are now beloved garden plants around the world, growing in many home gardens. Their popularity is largely due to their interesting flowers, which slowly expand like balloons before ‘popping’ into star-like flowers with five petals.
As blue is not a common flower color in the plant world, blue Chinese bellflowers with purple-ish hues are one of the most popular choices. But these interesting blooms also come in bright white and blush pink to suit any garden design.
White platycondons can be found in the wild across Asia, and are especially popular in Korea. The roots are commonly used as a vegetable called doraji, eaten fresh and dried. It is also used to treat various illnesses, such as asthma and bronchitis.
Balloon flowers are usually propagated from seed. It can also be propagated from cuttings but is not suitable for dividing as the long taproots are sensitive to damage.
Propagating From Seed
At the end of the flowering season, you will notice brown seed pods developing around the blooms. Once the seed pods have completely dried out, pull them off the plant and bring them indoors to open. Each pod will be filled with several tiny brown seeds in the shape of grains of rice.
From one flower, the number of seeds within the pod can surpass a hundred. As you likely won’t be planting over 100 seeds (unless you’re a huge fan of platycondons), save some in an envelope in a dry place to plant again next year.
Seeds can be started in seedling trays indoors over winter if saved from the previous year or planted straight into the ground in early spring after all frost has passed.
When planting in trays, sow the seeds lightly over a seed starting mix. Press gently into the soil to ensure as much contact as possible, but do not cover completely to aid germination. You should start to see small leaves emerging in around two weeks.
Once the sprouts have grown a few leaves, move them outside to acclimatize to outdoor conditions. After a couple of days, the seedlings can be planted straight into the ground. Be careful not to disturb or damage the roots during planting.
Keep the seedlings well-watered after planting and they will reward you with new blooms within the year.
Propagating From Cuttings
Although seed sowing is the most reliable propagation method, balloon flowers can also be propagated from cuttings. This is ideal for impatient gardeners (guilty) who don’t want to wait for the plant to produce seeds before propagating.
Using a clean pair of pruning shears, remove a cutting from the plant at least four inches long. Remove the soft stems close to the base for the best chance of rooting.
Remove any leaves from the bottom half of the cutting and dip the end in rooting hormone powder. Rooting hormone stimulates growth and makes success with propagation far more likely. It also helps develop stronger root systems; important for Platycodon Grandiflorus in particular as they have deep taproots.
Plant the cutting into a pot or tray filled with a moistened mixture of peat moss or coconut coir and perlite. This improves drainage, preventing root rot, while giving the cuttings the right consistency to develop roots.
Once new growth and leaves appear, the cuttings can be planted into pots or into the garden. It’s important not to damage the root growth while transplanting, as this can lead to problems with establishing once the plant is moved. Water the cuttings well after transplanting.
Plant seeds or seedlings in early spring once the ground has warmed. Enrich the soil with organic matter such as compost before planting to loosen the soil and improve nutrients. The deeper you loosen the soil, the easier it will be for the roots to grow downwards and for the plant to become established.
Plants should be spaced around 20 inches apart. Smaller varieties can be planted closer together, but other larger ones will need more room to grow. Check the label for the size of the mature plant, and use that number as your spacing guide.
While the soil should be loose underneath the hole, the plants can be placed at the same depth as the original pot or tray to avoid burying the stems too deep. Sow seeds on top of the soil as you would in trays.
Water thoroughly immediately after planting to give the plants a good foundation for growth. This is especially important when planting seeds as they need moisture to trigger germination.
Seeds should be thinned once they start sprouting to ensure there is adequate space between plants. This improves airflow and limits competition once they reach their mature size.
Planting in Pots
Balloon flowers are suitable for planting in containers and make great patio displays. Choose a dwarf variety that will not be constrained by the pot size. Shorter plants also look better in pots from a design perspective as the tall stems of larger varieties can look out of place in a shorter pot.
Choose a deep pot with enough space to accommodate the roots. About 12 inches deep should be enough space for most dwarf cultivars. Ensure the pot has enough drainage holes to prevent the roots from sitting in water.
If you’re recycling a container or making your own pots, you can always drill more drainage holes in the bottom. Space the holes equally to prevent water pooling on one side and encourage bacterial and fungal growth.
Fill the pot with a well-draining potting mix. It should be light and airy to improve drainage and stop the pot from becoming too heavy when watered. Never use soil straight from the garden as this can cause problems with drainage or pests and diseases. Heavier soils can be amended with coconut coir and perlite to improve drainage.
You can sow seeds straight into the pot to avoid disturbing the roots later on, or sow into trays and transplant into larger, final pots when the seedlings are ready.
How to Grow
When growing Platycodon Grandiflorus, there’s no “simple” way to make flowers that grow beautifully. Your plants need the right combination of light, water, soil, climate, and fertilization. Let’s take a look at what you’ll need to grow these flowers successfully in your garden in each category.
Chinese bellflowers perform their best when planted in full sun. This will improve growth and ensure you get the most flowers possible.
At least six hours of sunlight is recommended, but this can be too much for the plants in very hot climates. In extreme heat, these plants will benefit from plenty of morning sun, with some partial shade in the afternoon.
Newly planted platycondons prefer consistently moist soil. They will need to be watered relatively often, especially in the first few weeks of planting. But, once the long roots have grown, you can limit watering. The taproot will access deeper parts of the soil where water does not evaporate as quickly. The top layer of soil can dry out and the plant will still be satisfied for several days.
Once established, rain should take care of most of your watering in moderate to high rainfall areas. In drier periods and in hot weather, they will need slightly more water to prevent stress but are considered slightly drought tolerant.
Like most flowering perennials, Platycodon Grandiflorus prefer loamy, well-draining soil. Due to the thick roots, clay soil is not recommended as the extra moisture retention and compaction can lead to rotting. pH is not much of a concern, but they do prefer more acidic soil to more alkaline soil.
Climate and Temperature
Balloon flowers grow best in mild climates, from USDA Zones 3-8. Excessive temperatures (above 85F) for long periods of time can cause heat stress, preventing flowering, while frost can kill off tender new growth. However, they are known to survive temperature changes well and will return to normal when the conditions improve.
Humidity is not much of a factor – platycondons can handle humid or dry areas. Humidity can potentially cause problems with diseases though, and extra care should be taken in these areas.
If planted in good, nutrient-rich soil, there is no need to fertilize. In fact, fertilizing when conditions are already good can result in problems with growth. Excess nitrogen can cause plants to grow outwards, rather than upwards, which can be a problem in interplanted garden beds.
If your plants are not growing, you can either enrich the soil with compost by adding it around the plants as a mulch, or apply a slow-release fertilizer once in spring to improve conditions.
Balloon flower maintenance is mainly about keeping the plants looking their best and is not always 100% necessary. You can prune the stems back in the latter part of spring to promote denser, more compact growth, but the plants should grow just fine without this trim in the right conditions.
If the stems appear to be stretching or look leggy, pruning should resolve the issue. In fall, cutting back all the dying stems to ground level will set the plant up for success the next season.
More controlled trims can be done in early or late spring, depending on the plant’s performance. However, spring pruning needs to be done with precision, as damaging the early growth will cause more problems later on in the season.
If pruning does not resolve the issue, your soil may contain too much nitrogen. Conduct a soil test to determine the nutrient levels in the soil and adjust accordingly to restore the necessary balance for strong upright growth and flowering.
You can also deadhead spent flowers throughout the season to promote more blooming and keep the plant neat. However, if you’re looking to sow seeds the following season, keep those blooms on the plant until the pods have dried out and are ready for picking.
If you’re not looking to collect seeds, it’s best to remove the flowers at the end of the season. The seeds can spread quite vigorously if left alone. You may find yourself removing germinating Chinese bellflower seeds from strange parts of your garden if their spread is not controlled.
Regular mulching with organic materials will help retain moisture in the soil without becoming waterlogged. Compost is ideal as it slowly breaks down into the soil, improving nutrient availability and soil structure at the same time. However, other organic materials like bark chips or straw are also great options.
Mulching also has the benefit of keeping weeds at bay, limiting your need for weeding during the growing season. Keep the layer of mulch from building up around the stems to prevent rotting.
Most platycondon cultivars look quite similar, with blue or purple star-shaped flowers emerging from enlarged buds. However, horticulturalists have produced some truly stunning varieties for gardeners to enjoy, from bicolored flowers to extra petals.
For the classic balloon flower look, you can’t go wrong with ‘Fuji Blue’. These blue flowers have a purple tinge to them and can look like either color depending on the lighting. The petals are also quite transparent, making for an interesting garden display in the sunshine. ‘Fuji Blue’ is on the taller side, growing to a maximum height of 24 inches.
‘Sentimental Blue’ is another blue cultivar that looks quite similar, but is more compact. This variety grows to a maximum of 18 inches tall, but usually stays on the shorter side – perfect for filling in gaps in your garden beds.
Not all balloon flowers have five petals – some cultivars have ten instead. The hybrid varieties, known as double flowers, are the result of cross-pollination. The typical flower shape is surrounded by another set of petals that fill in the gaps for a captivating show during summer. Try ‘Astra Double’ for a dwarf variety, or ‘Double Blue’ for a taller plant growing to a maximum of 30 inches.
Stepping away from the blue flowers, we have two stunning cultivars. The first is ‘Fairy Snow’, a dwarf plant with delicate white flowers and blueish-purple veins lining the petals. ‘Astra Pink’ doesn’t grow very tall, but sports large yellow balloon flowers that pop into pastel pink blooms.
Finally, we have a personal favorite – a rare cultivar known as ‘Mother of Pearl’. The flowers are pale pink with striking deep pink veins that taper toward the edge of the petals. This cultivar is sure to make a statement in any garden.
Pests and Diseases
Platycodon grandifloras experience little to no problems with diseases in the right conditions. Most popular cultivars also have some degree of resistance to diseases, almost eliminating the problem altogether.
In wet, humid weather or in times of stress, you may find issues with root rot, crown rot, or powdery mildew, but are they unlikely to affect your plants in most regions.
In terms of pests, platycondons attract slugs and snails in rainy weather. However, these pesky pests can be lured away from your plants using a beer trap, stopping them from nibbling on your foliage.
To make a beer trap, grab a deep tray or a small bucket and a can of beer. Dig a hole somewhere in the bed and bury the tray or bucket so the top is in line with the soil. Fill it with the can of beer and wait until nightfall when the snails are most active.
The beer will draw any nearby slugs or snails away from your plants and to the trap. And the move inside the bucket, they will ultimately drown in the liquid – a sad end, but at least they will die doing what they love.
Balloon flowers have many uses in the garden. They work well when planted amongst other tall perennials in beds of containers, with the flowers mixing for an informal, interesting display. Their relative drought tolerance lends them to use in rock gardens or planting alongside grasses.
For dwarf varieties, opt for a mixed planting in containers. The large blooms can either complement other flowering plants or stand out amongst foliage. Ensure each paired plant grows in the same conditions to prevent one from thriving at the expense of the other.
Taller balloon flowers look great when mixed in with other perennials in a large bed. When paired with shorter flowering plants, the blooms will round off the color as a metaphorical and physical ‘cherry on top’. Be careful where you place them, as the spreading seeds can quickly take over a bed if left unchecked.
Beyond the garden, the root of the plant is often used in Asian cuisine. The root is soaked in water, washed, and covered in salt to draw out the bitterness, much like the process of removing bitterness from eggplant. It is used as a vegetable in some dishes, or added to desserts and alcoholic drinks, depending on the type of preparation.
The roots are packed with nutrients like calcium and iron. They are used in natural medicines for colds and flu and for improving the immune system.
Studies into the benefits of balloon flower root show it may aid in pain and respiratory relief. There is also limited evidence that it may help those with allergies by inhibiting histamine response.
Frequently Asked Questions
Are balloon flowers hardy?
Platycondons are quite hardy and can withstand colder temperatures, growing in USDA Zones as low as 3. They do not do well in higher temperatures and handle cooler weather better.
What can I plant with balloon flowers?
Balloon flowers are great companions for most flowering perennials, as long as they do not require too much water. Bee balm, daylilies, and salvias are all great options. You can also plant multiple cultivars of different colors together for a uniform display with pops of color.
Will the flowers rebloom?
Chinese bellflowers are perennials and will continue to flower year after year. They may die back a little in the cold winter months but will grow and flower again the following spring.
Should I deadhead balloon flowers?
While it is not absolutely necessary, balloon flowers will perform best when deadheaded regularly. Some cultivars, particularly the double bloom types, respond well to deadheading. Remember to avoid this step if you are planning on harvesting seeds from your plant.
Balloon flowers are the ultimate flowering perennial plant. They are incredibly low-maintenance, propagate well, require little attention, and flower reliably year after year, even within the first year of planting. Plus, their cute balloon-like blooms that explode into colorful star-shaped flowers are second to none. What’s not to love?
Plant yours from seed or seedling in containers or in garden beds and they will reward you in spring. Bring a few buds indoors before they open for a wonderful cut flower display, or leave them on your plants for carpets of color throughout the season. They may die back in winter but will return again in a few months to brighten your garden, and your day.