Both the quality of lighting and contrast with adjacent colours can greatly affect our perception of colour. When in doubt , compare the colour with an actual physical colour chart or colour wheel.
Having said that, I will say that the majority of tones in the first Iris would be accurately described as blue-violet, while those of the second iris would be considered violet. The term 'Purple' is generally considered a synonym of for red-violet.
In horticulture, the term 'blue' is vastly overused to describe floral colour, the majority of which are actually to some degree violet. However, there are many 'true' blue flowers too, and even a rare few that can be accurately described as blue-green, turquoise, or teal.