Thanks Hoy.
I have another plant which I have gotten as F.kamtschatica and which has white flowers and is over 2 m high when flowering, also the leaves are bigger, but I will have to compare it's leaves to this plant when the summer comes.
If this seed grown Filipendula with pinkish flowers grows as big I will have to move it to someplace else.
Last summer was only the second time it flowered so it is a young plant still, and that may be why it isn't yet so big..