Shrimp plants won't bloom

I planted shrimp plants 3 years ago in different areas with light conditions ranging from light filtered shade to full sun. They bloomed the first year, but they haven't bloomed since. Otherwise, they're vigorous healthy plants. What should I do to make them bloom?

Mine have multiplied, but not bloomed either.

I think we need to apply a fertilizer with a high phosphorous content. Miracle Grow bloom booster was recommended by a friend. My shrimp plants are borderline invasive, but I welcome each and every one. I also grow gold shrimp plants, but I bring them indoors during winter. All shrimp plants root very easily.

fertilized mine today with miracle grow and fish emulsion.. now if it will cool down just a little....