You're right. After having no success with my books I tried plumbago on
google images and every close up has five. I tried looking up four blue
petals and got no where. The pic supplied still looks like a plumbago
though, so maybe it's a freak! Or as the one clear flower is the same
one in each pic, maybe we could ask gigling mom to have a look at the
other flowers? Maybe carefully unfurl the curled up ones? Do they all
have four petals?

Charles wrote:



The pictures I find of plumbago have five petals, the flowers in the
OP's shot had four. Is there some variation, or am I missing
something?