I'm wondering whether you mean Commelia communis, or whether you mean Camellia - the former is considered a weed plant, also known as the Asian Day Lily, and is an annual, seeding itself liberally. Annuals of this sort generally prefer soil that isn't particularly fertile in order to produce flowers.

If you mean Camellia, that's a different story, so please clarify if necessary.

I think the pretty blue plant is Commelina, not Commelia.

I didn't know this one so looked it up and found what looks like the same plant under both spellings!

(ie Commelina and Commelia)