I use azomite for my bloom booster for the following year's blooms. I would also suggest cutting off the flowers after they bloom, so it doesn't expend energy on seeding.

Thanks. I will try some bloom booster. When do you use it? In Spring before the bloom?

I did cut off the spent flowers, thanks!

I am using mine all throughout the year, just a little bit at a time because I believe that the flower buds of next year start developing as soon as the flowers of the current year starts wilting.

I purchased a 44lb bag of azomite off of eBay since I have so many peonies, tree, itoh & herbaceous types to take care of.