Mine isn't flowering but I just read today that "The flowering process can often be halted by heavy application of lawn fertilizer, followed by ample irrigation. This should be done at the first sign of flowering". It didn't say how much is heavy application of lawn fertilizer. This was from The University of Georgia College of Agricultural and Evironmental Sciences. Hope this helps.

I've heard about the fertilizer approach...but I've yet to reliably hear that anyone was ultimately successful with it. Mine flowered about 3 years ago and is pretty much dead. The only thing good that came out of it is that I collected lots of seed and have many little F. nitida plants that will hopefully not flower again in my lifetime. I'm also hoping I live long enough to see them get as big as my old plants. Right now my biggest is all of 18" tall!