Personally, I like the larger forms better, though they aren't easy to find. Dwarf forms look stumpy.

Balloonflowers can bloom for a very, very long time if they are kept deadheaded. Here, they will often bloom into September. Then they are one of the few perennials with good fall color - bright yellow.

I used to not care for the popular dwarf (6"-12") cultivar 'Sentimental Blue' but it has grown on me for specific applications. The flowers are huge relative to the plant's height. It resembles an annual in size and if deadheaded it will bloom for nearly the entire summer. I use 'Sentimental Blue' in more formal garden beds in combination with annuals of similar size and stature because there are so few blue/purple annuals available. I do prefer the taller cultivars such as 'Mariesii' for informal wildflower borders -- though even those are somewhat dwarfed (18-24 inches) from the species (30-42 inches), which has a tendency to flop. The link below compares some of the various cultivars, though many newer ones are now available.

Here is a link that might be useful: Balloon Flower Comparison

Thank you 'mad' and 'mista' for the information. Given the location I have in mind they really should be a dwarf variety. But it is good to know that the bloom time is very long.

Right now I am thinking of either the dwarf 'Astra Double Blue' or the somewhat larger 'Platycodon grandiflorus'.

Platycodon grandiflorus is the botanical name for the species from which all of the cultivars (such as 'Astra Double Blue') are derived (just to clarify any confusion). It has become very hard to find the straight species these days. Also, keep in mind there is great height variance among so-called "dwarf" cultivars. Some are 6 inches high and some are 24 inches. Often, the cultivars are mislabeled by the grower and often they grow taller than specified on the plant tag.

So mistascott this is too general?:

Here is a link that might be useful: a balloon flower?

I have, and have grown for several years, Playcodon Fairy Snow. It is in the front of the border, and looks good there. I enjoy seeing the buds swell and then open up every summer. My neighbor also has it and she has planted seeds from her plant to increase the number of plants that she has. I have never deadheaded my plant because I keep the seeds for seed trading purposes so I don't know if dead heading this particular variety would prolong bloom time.The plant is a personal favorite of mine.

Our summer was very brutal to many of my perennials, including my P. Fairy Snow. It's in full sun and we had weeks of 90+ temps along with little rain during June and July. The flowers didn't stay open for very long during the heat, something I've not noticed in the past.

I also have P. Fuji Blue and have it at the back of the border since it tends to fall over. One of these days I need to get some plant supports and put them to good use!

Linda

I have P. grandiflorus as well as Hakone white planted in both full and part sun. To prevent flopping, established plants can be whacked down to 12" in late May/early June (Z6) which will also increase the number of blooms they produce. They normally begin blooming toward the end of July and are still producing flowers through early September.

I too harvest the seeds for trading and through winter sowing have increased the number of plants in my various beds over the past few years. The clean white & true blue are definite stand-outs in the perennial beds. This year I also added Axminster and look forward to those blooming next growing season.

One feature no one has yet mentioned is that P. grandiflorus isn't bothered by any crawling/slithering/flying pests or four-legged varmints that I've noted in the 18+ years I've enjoyed it in my garden, and apparently isn't affected by any foliar diseases.

rogue21: Your link shows the straight species. It isn't too general; that is just the original plant that occurs in nature. All of the others, such as 'Sentimental Blue' and 'Astra Double Blue' are cultivars (cultivated varieties) of the original Platycodon grandiflorus species meaning that they were developed through selective breeding of P. grandiflorus. This is probably more detail than you care for, but I hope it helps.

rouge21 -- sorry for the misspell