chemical to increase flowering, fruit set, and root growth?

High GA3 concentration is known to inhibit flowering of roses, see for example:

There is a chemical that is a known gibberellic acid biosynthesis inhibitor. It is prohexadione-calcium (ProCa). A 2005 Ph.D. thesis that investigated this compound is available for free download at: Http://

The author studied strawberries but the thesis may give some information at least worth trying on roses. I particularlly recommend reading the 2 chapters starting on page 81 and on page 89.

The following link gives the available commercial products: