It's a good symbolism for finding the middle ground where they can make things work despite their differences between them.
With the added bonus where the plant can grow and change as their love grows and changes.
Learning and working together to keep it alive.

GloBite-
GB = N/A [Want to come up with one but am having trouble]
DB = Minnow

Blhoover-
BH = Captain [When BG wants something from him]
BG = [No true pet name but BH will use the description, "My sweet little" before referring to him]

PippaMeam-
PF = Phoenix/My Hero [MA uses in a joking manner]
MA = Ambie