The variety of colors irises are available in is remarkable, but Graeme Grosvenor states in the 1997 book Iris: Flower of the Rainbow, “Red in the sense that we think of it as pillar box or fire engine red is a colour that is not, as yet, found in iris. There are quite a lot of iris which are loosely described as red but it is a class which, in general, has lacked vigour, been difficult to increase and carry over and particularly difficult to grow in milder climates.” So, “red” irises are often rather more orangey or purplish than a “true” red would be. That being said, there are some startlingly red cultivars out there. They may not be “fire engine red,” but they sure look red to us!