Poly, my understanding is that reblooming irises need another bit of fertilizer after they are through with their spring bloom cycle and enough water during the hot dry months to prevent them from becoming dormant. Non rebloomers are happy with just spring food. That is one reason I started moving my reblooming irises to the same location..... easier to toss some food in one area and to give that area a drink when I am watering the general garden.
