Ok i just couldnt contain myself anymore and bloomed my waifu Helenium even though her bloomed abilities are worse or broken. I just hoped that it would only be an error in the description.
So here is the result of my test:
It seems that she still retains her attack bonus. Before it was 30% for 3 allies including herself, now it seems to be 60% for 3 including herself and 20% for the rest. Btw she also gets the skill activation rate 1.2x. It came right after that, i just didnt screenshot it.
So at least thats a good thing.