I planted Amalia Olson in the fall of 2016, was astonished with its perfect form and bright white color next summer. (I live in Alaska.) In summer 2018 I left also one bud to save some energy for development and the flower was not as perfect as the year before.  This summer I was surprised with the flowers – they were not pure white. I am sure the climate and other conditions affect the blooms, last summer was cool and probably the peony did not store enough energy for flowers. I am waiting for the next year, the bush is growing and I hope it will develop soon to produce perfect flowers again!