[oh, kaeya... he tries to act all cool and suspicious while also seeming flirtatious and sultry. but in the end, he's a sweet, good boy, helping out those in need. he's always been like that, it's just in recent years that he's desperately tried to hide that side of him.]

I wouldn't say he's a "plant guy" in particular. But perhaps he's attached sentimental value to those specific flowers.

[were they similar to calla lilies? or perhaps... to lamp grass even?]

He can be surprisingly... whimsical, I suppose you could say.