Apparently, no. I have jpn account too and newer reissued girl use only 1500 sealstone to get, with lesser for dressbloom/skillbloom too.
And if nothing changed, next week when 2nd phase come, you can also trade event-exclusive accessories too.
In short, Nutaku pretty much bring this event up prematurely. Next from Dipladenia should be Mirabilis, not Gentian.