Yes, it's going to branch somewhat, into smaller, terminal branches that bear flowers.

There really isn't much to say. The genus is Boltonia, but for all intents and purposes, it's an aster, has the same growth habit, same needs, etc., as New England and New York asters, treat it as such and it will do fine. As with New England aster, it will benefit from a couple of early pinches to make it a bit more bushy and full. Oh, and rabbits and woodchucks used to eat it in my garden (I no longer have it, it died out).

ditto. i really like it.Def not invasive imo.I WISH! i have the opposite problem.

It is my second try with it, the first did not thrive at all for some reason(too dry?). But while it lived, it looked like it could be a runner(far apart between the stems).

I bought a couple two years back. They do really great.. but this is the first year that i have cut/pinched back the top a bit to encourage branching. In the past the plant would get 3+ feet tall, bloom out.. which looked great.. but as soon as you have a decent rain storm.. the plants get hammered down and you have to attempt to stake it.. which is nearly impossible with such a mop head shape.

I also have it planted near other plants that help support it a bit in the weather. If you had it out in the open, it might flop even with pinching it back.

It has spread very slowly, not seeded down at all. So it's been a good plant so far.

Snowbank is always advertised here in Europe as non-flopping. Does it mean it is just a lie?

Unfortunately, I think very few plants are "non-flopping" due to weather, etc. Most climates seem to dish up a weather event that forces plants over when they are heavy with buds or blooms.

And, I think that it's not actually very natural for many plants to be grown in monoculture without a lot of other plants mixed in. In a natural meadow or prairie habitat, forbs like Boltonia are growing mixed in among grasses, low shrubs such as brambles, and other forbs, and they form a sort of self-supporting mass of vegetation. They don't have that in most garden situations, many of us are somewhat like children who become upset if the peas touch the potatoes on the dinner plate and we give our plants the luxury of space. Great for the plants in many ways, but perhaps it does contribute to the tendency to flop over.

In my opinion 'non-flopping' is not debatable or open for interpretation. It means that it is taken into account that there is rain and wind in nature and they also can come at the same time. Non-flopping means that the plant can remain standing position after rain and wind in 'average version', nobody would demand from a plant to remain standing in the tornado or a flood. If a plant can't stand on its own it's called 'may need staking' or 'requires staking'.

What makes me wonder while I'm reading English/American catalogues what do they exactly mean when they write the words 'sturdy stems'. When I translate it with google it makes no sense. What can I use 'sturdy stems' for in a peony that is laying on the ground after the first rain?

When I use the term non-flopping I mean non-flopping.
(does not assume permanent laying position)

pbl_ge, I also purchased the Snowbanks from Bluestone last year (when they still sold them in sets of 3). I bought two sets of 3. I pinched maybe 3-4 times before July 4th and by the fall the plants were beautiful, about 4 feet tall, very full and impressive. I also particularly like the foliage on the plant as it grows. The plant is airy and "branchy" (if that is even a word) and with the light blue/green color definitely sticks out in the perennial bed. And in terms of flopping, mine only flopped after we got hit with Hurricane Irene (and that was more from the wind then the rain), but they even recovered from that. I think growing them close together helps them support each other as someone else mentioned above.

What I would be careful of though is your placement. Man does this plant spread rapidly. This spring I had to divide up both my Boltonia and my Woods Blue Aster I also bought from Bluestone last year.

6 Boltonia plants last year -> ~easily 30+ multi stem plants this year (all doing great after the move). I had to move them all over the yard, even made a long hedge since I was out of space. I am guessing next year I will be begging people to take some of them from my yard.

Same thing with my Woods Blue. 3 plants last year -> 27 plants this year. Again all doing well and filling in nicely.

Good luck!