Because they are so old, irises have become quite heavy with symbolism and legend, so much so that I almost got drowned in the downpour of information that carried me from the gods and goddesses of Antiquity to the budding medicine of the Middle Ages, to the royal house of France, and then back to perfumers and ancient chemists, bouncing about between Christianity and magic. Several hours later I abandoned the search that almost gave me a headache.
I emerged from the vast sea of the Internet confused and bewildered, dragging little bits and pieces of information behind me, and since I wouldn’t want good effort to go to waste, I’ll share them in as compact a form as I can.
First, irises are as old as the pyramids and strangely enough, they did grow in Egypt; the Greeks venerated them as the flower of Iris, the goddess of the rainbow. Because the latter was in charge of carrying the souls of departed women to the Elysian Fields, Greek men used to plant them on the graves of female loved ones, a tradition that lasted through centuries to this day and explains the abundance of irises in cemeteries. Of course, the fact that they come in every color of the rainbow, look fetching even when not in bloom and require absolutely no care didn’t hurt.
In the Middle Ages the plants were used medicinally, they were believed to treat dropsy, asthma and venereal disease, but the real popularity of the flower came from its qualities for perfumery: orris root extract is a substitute for violet perfume. Its scent is very pleasant all by itself, but it also enhances other fragrances mixed with it, which is why it is valuable as a fixative for perfumes, powders and potpourris.
Some say that the juice of iris flowers soothes many skin afflictions from acne to dandruff, but I don’t remember seeing irises in a medicinal plant compendium, so I’ll take that under advisement. As far as superstition is concerned, chewing on iris root will make you stutter.
Apparently the fleur-de-lys was an iris, not a lily, and I can believe that because lily flowers don’t have a second set of petals growing upwards, and as much as it was connected to pagan tradition via the ancient goddess of the rainbow, it still became the symbol of conversion to Christianity when the house of France adopted it to embellish its coat of arms.
Iris was a messenger of the gods, who traveled by wind and by rainbow to pass along their words to mortals, creatures of the sea, and even the underworld, and this is why in the language of flowers irises symbolize communication and wisdom. They also stand for faith and hope, especially the blue ones.
I’m sure I missed a bunch of stuff. Hours, I tell you!
Oh, yeah. Irises are the birth flowers of February.

Author's Bio: 

Main Areas: Garden Writing; Sustainable Gardening; Homegrown Harvest
Published Books: “Terra Two”; “Generations”; "The Plant - A Steampunk Story"; "Letters to Lelia"; "Fair"; "Door Number Eight"
Career Focus: Author; Consummate Gardener;
Affiliation: All Year Garden; The Weekly Gardener; Francis Rosenfeld's Blog

I started blogging in 2010, to share the joy of growing all things green and the beauty of the garden through the seasons. Two garden blogs were born: allyeargarden.com and theweeklygardener.com, a periodical that followed it one year later. I wanted to assemble an informal compendium of the things I learned from my grandfather, wonderful books, educational websites, and my own experience, in the hope that other people might use it in their own gardening practice.