Lately the balloon flower—Platycodon grandiflorus—has been stalking me. As I wander through garden centers in search of mid-summer bargains, the inflated buds pop out from the pallets. A neighbor’s border overflows with a blue-flowered variety. Last week, on a visit to the main garden of the Cloisters museum in Upper Manhattan, I saw a giant healthy clump resplendent in the mid-summer sun.
Perennial balloon flowers are perennially popular, but since I last wrote about them six years ago, they have clearly taken off. Roger Phillips and Martyn Rix, writing over a decade ago in their wonderful book, The Botanical Garden, mentioned that balloon flower is popular in Europe, North and South and Japan. My hometown may not be a microcosm of the rest of the world, but balloon flowers hold court in both north and south ends and at various points in between.
The balloon-y buds are distinctive, but when balloon flowers open, they betray their close ties to other members of the bellflower or campanula family. Each flower features five pointed petals, joined to form a bell-shaped base. The oval leaves are green with a blue cast and the seed capsules that develop after the blooms fade are a striking steel blue. Rising from plump, fleshy roots, the stems can range from about forty inches tall in the species form to only 12 inches for little ‘Sentimental Blue,’ a form that is suitable for containers, small gardens and border edges. Happy balloon flower plants form clumps that increase in size over time.
There are lots of campanula species on the market, but the platycodon genus has only one species, grandiflorus. The generic name, “platycodon,” comes from the Greek, by way of Latin, and means “broad and flat,” a reference to the plants’ broad, flat, bell-shaped flowers. Sometimes called Japanese, Chinese or Korean bellflowers, balloon flowers are native to eastern Asia and Japan and first arrived in the United States in the late eighteenth century. They have been modestly popular here ever since, though perhaps not as widely used as bellflower relatives like lady bells, Canterbury bells and the little Carpathian harebell varieties like ‘Blue Clips.’ That modest popularity seems to be increasing now, judging by what I have seen lately in the garden centers.
English writer and gardener Vita Sackville-West used a white form of balloon flower, ‘Mariesii Alba,’ in her famous white garden at Sissinghurst. The standard ‘Mariesii’ variety, an old favorite, grows about eighteen inches tall and features purple flowers with darker purple veins. It is a recipient of the Royal Horticultural Society’s Award of Garden Merit—AGM—for overall good garden performance.
A number of single and double-flowered platycodon varieties are available in the American market, in addition to the single-flowered ‘Mariesii.’ One of the best known doubles is ‘Hakone Blue,’ which is tall, at forty-two inches. Its sister plant, ‘Hakone White’ grows to a similar size, but bears white flowers. Recently single, pink-flowered balloons have shown up in many places. Rosy cultivars include ‘Shell Pink,’ which is a little shorter, at twenty-five inches tall, ‘Astra Pink,’ even shorter, at six to twelve inches tall and the semi-double-flowered ‘Astra Double Pink.’ All feature darker pink veins. No matter how tall your balloon flowers grow, most have flowers that are about three inches wide when fully open.
Balloon flowers flourish in mid-summer and require sun or very light shade to do their best. I have grown mine in both situations and the plants in sunnier sites always produce more flowers. Their needs are few, but relatively rich, well-drained soil that is consistently moist is important. The species has a reputation for being finicky about relocation, but I have moved and divided established clumps successfully. Taller varieties, like the blue-purple ‘Komachi,’ are also prone to flopping over. You can deal with this in one of several ways. Position them at the back of the border, near other plants or structures that will prop them up. Barring that, support them with stakes or grow-through plant supports installed as soon as they emerge in late spring. If you are a vigilant gardener, you can also do the “Chelsea Chop” on balloon flowers, cutting back the stalks by about one third in May. This takes a bit of courage and delays the bloom time, but results in shorter stalks that may not need staking.
Balloon flowers are suitable for formal and informal gardens, as well as containers and cutting beds. Children love the balloon buds in the same way that they love snapdragons and other eminently touchable flowers. Good companions include yellow or gold-flowered varieties of yarrow and coreopsis. Balloon flowers also work well in arrangements, but the stems should be singed over a flame after cutting to stanch the flow of milky sap.
Get your balloon flowers right now in garden centers, where you may be able to pick them up for a bargain price. Otherwise, order them for fall delivery from mail order nurseries, most of which carry a couple of varieties. One good source is Niche Gardens, 111 Dawson Road, Chapel Hill, NC 27516, (919) 967-0078, www.nichegardens.com. Free catalog.