I have always read that the new blooms get initiated way down in the rizomes of the new starts in the six weeks following bloom of the mother rhizome, and that's why one should fertilize after bloom with a fertilizer that is higher in phosphate than it is in nitrogen. The first number is nitrogen, and you doubled it. That probably threw a lot of energy into leaf production.
But it's probably more how you treated them last june and july that affected bloom this year. And are they getting enough sun?
