Hi,
I'm looking for fertilizer for flowering trees.
Something with high "P" so I can force more flowers to open at same time.

You will not force flowers to open at the same time with fertiliser. Conditions like sun and temperature as well as day length have an influence on flower opening. You don't say what plants you are referring to. My Hawthorns were all open at the same time as were my Pyracanthas The Satsuki are also opening well

I've got 2 Carmona microphylla.
All what I'm getting 3-5 flowers at a time.
Like they take turns or something.
I've seen pictures on internet when all tree is in flowers. 0

Probably you have very young plants. They are a difficult species at the best of times.