Greetings Brenda:
Yes, there are such products and they are commonly referred to as plant growth regulators. A commonly marketed plant growth regulator is Florel. Since I do not have have any experience with such products, I am at a loss to offer any objective opinion. However, I have heard, or read, many mixed results as Florel plant applications need to be timed perfectly with plant flowering.
I would strongly suggest contacting a local university horticulturist for more information regarding plant growth regulators.