Apparently there is some prequel novel to this called "Common Sense of a Warrior" where Iris's mother, who was previously introduced in this story as the only daughter of a general, was born to a military family and an aspiring warrior/soldier - synopsis says she was talented at swordsmanship before she got married to the father who was going to be the duke.
So, that means not only is she the flower of high society, but apparently she was a pretty badass woman too.
I maybe looking too much into it, but maybe that's why her daughter asked the staff to prepare roses for her - befitting for a beauty with pretty wicked thorns.