Yes it is. I couldn't capture the richness of the colour, but the hue is magenta. I love it. I was wondering about that as the flower has been described to me as maroon (for this plant, too, when I had bought it), but mine isn't. It has been cloudy lately, the light has been blue, and the colour hasn't been turning out right with my camera phone so I haven't posted Koukamon again. Once I get my big camera sorted, I'll take another photo. Also, because of the cool weather, the flower hasn't really opened yet. Yesterday it rained, but the flower didn't sag like the others because it's still basically a big gorgeous ball of flower. My Chojuraku hasn't fully opened either. Yachiyo has always been a huge messy flower (avatar pic) and didn't look any different after the rain
I had put stuff in the soil including green sand and a trace mineral fertilizer like azomite (but it's local as azomite isn't found here), and the soil I had used had compost and was hot with bioactivity. One of the tree peonies I had gotten exhibited iron chlorosis, but this year looks like a completely different plant, so the soil is definitely having an effect, to what extent on its hue, I don't know.