I'm not sure if this is a bug or something I haven't spotted in the config files, but the Floral Reproduction modifier seems not to work on any Biomes o Plenty flowers

I believe it may potentially be hardcoded to only work on Vanilla plants; getting it to work on other plants proved quite problematic. Given that we're diving pretty heavily into the 1.16.5 port, I don't know that there will be any intent to change this.