Originally Posted by Drip

Basically the same as Fritillaria, though at only half the increase rate. In an ability trigger team with leveled skills, Fritillaria usually reaches her 30% bonus somewhere between 5 and 8 rounds.
So for Gerbera, I figure it'd take as much as 20 rounds (first and third round trigger passives work only on those two turns, so can't just "double" Fritillaria's amount of combat rounds because of those). And 20 rounds of combat? Not gonna happen any time soon I'm afraid.

Good lord. Only girl I'd probably be interested in seeing fight 20 rounds is a life-leeching 6* like Alpinia or Kerria.

And yes, it's neat how bonusses trigger even when the girl has already been taken out of battle. It works like that for other passives as well, so a girl who just got taken out of combat may still buff another girl because her passive triggers. Works at least like that within the same battle, not sure if it keeps applying throughout the map between battles.

For this one, and in Gerbera's case, she could really use an AOE ATK buff instead of a self-buff and still be useful to the rest of the squad even when she's gone.