What does iris smell like? The costly root behind powdery perfume

Iris is the most surprising note in perfume. The beautiful purple flower you see in gardens is not where the scent comes from. It comes from the root, which is dug up, dried and left to rest for years before it smells of anything at all. The result is one of the most elegant and expensive materials in the world.

What does it smell like?

Soft, powdery and cool, with an earthy depth. Iris is less "flowery" than most florals. Instead, you might notice:

• Powder: like face powder, a soft, dusty, cosmetic smell
• Lipstick: a waxy, slightly sweet, make-up bag note
• Earth and roots: a damp, cool smell, like raw carrots or freshly dug soil
• Violet: a gentle, sweet floral glow
• Butter and suede: a smooth, rich, slightly leathery texture

People often call iris "grey" or "silvery". It feels cool, calm and refined, rather than sweet or warm. It is the smell of elegance more than romance.

Where it comes from

Perfume iris is called orris, and it comes from the underground stem (rhizome) of two species:

• Iris pallida, the pale or Dalmatian iris, the most prized. It is grown in Tuscany, around Florence, and is native to the eastern Adriatic coast.
• Iris germanica, a related species with a slightly different smell. It is grown in Morocco and China, and also in Italy.

Tuscany has the most famous reputation. The fleur-de-lis on Florence's coat of arms is widely believed to show an iris rather than a lily. Iris has been grown there for perfume and medicine for centuries.

How orris is made

Making orris is one of the slowest processes in perfume.

1. Growing. The plants are left in the ground for around three years before the rhizomes are dug up by hand.
2. Drying and ageing. The rhizomes are peeled and dried, then stored for two to five years. Fresh iris root has almost no scent. During this long rest, odourless compounds in the root slowly turn into irones, the molecules that give iris its smell. Older roots usually give richer orris.
3. Distillation. The aged roots are ground and steam-distilled. The result is waxy and solid at room temperature, so it is called orris butter (or orris concrete). It contains fatty acids that make it look like a pale, waxy butter.
4. Absolute. Orris butter can be further purified with alcohol to remove the waxes, giving orris absolute, which is richer in irones and even more costly.

From planting to finished butter can take six years or more, and the yield is tiny. By some estimates, a kilo of the finest orris butter can cost tens of thousands of euros, making it more costly by weight than gold. This is why real orris is used in small amounts and why it is so admired.

A short history of iris

• Ancient world: Iris root was used in perfumed oils and medicine in ancient Egypt, Greece and Rome. The Greek goddess Iris, messenger of the gods, gave the flower its name, which also means "rainbow".
• Renaissance Florence: Dried iris root was used to scent linen, as a fixative in powders and potpourri, and in tooth powders and breath fresheners.
• Orris powder: For centuries, powdered orris root was used to scent hair powders, wigs and cosmetics. That is partly why iris still makes us think of face powder today.
• Modern Tuscany: Italian production has shrunk sharply over the last century, as farming iris is slow, labour-intensive work.

Iris in modern perfume

Iris has been a perfumer's favourite for over a century.

• Après l'Ondée by Guerlain (1906) used iris and violet notes to create a soft, misty, melancholy mood.
• Chanel No. 19 (1970) is famous for its sharp green iris.
• Iris Silver Mist by Serge Lutens (1994), by perfumer Maurice Roucel, is a cool, earthy iris that many consider a reference point.
• Dior Homme (2005) made iris a hit in men's perfume, with a soft, powdery, cocoa-tinged iris.
• Infusion d'Iris by Prada (2007) made iris light, clean and wearable for every day.

Real vs synthetic iris

Because orris is so costly, most iris notes in perfume are built with help from synthetics.

• Ionones and methyl ionones give powdery, violet-iris effects. Some are designed to smell almost exactly like orris.
• Synthetic irones recreate the core of the orris smell.
• Some perfumes use a little real orris, boosted with these molecules.

Iris and violet are close cousins in perfume because they share similar molecules. This is why many iris perfumes also smell a little of violet, and vice versa.

What iris pairs well with

• Violet: the classic powdery pairing.
• Leather and suede: make iris soft, rich and luxurious.
• Woods and vetiver: keep it cool, dry and earthy.
• Rose: creates a lipstick-like, vintage glamour.
• Vanilla and cocoa: make it warm and comforting.

Perfumes to try

From easy to serious:

• Infusion d'Iris by Prada (2007): clean, airy and office-friendly. A great first iris.
• Dior Homme by Dior (2005): powdery iris with a touch of cocoa. Worn by men and women.
• Hiris by Hermès: cool, green and gentle.
• Chanel No. 19 by Chanel (1970): sharp, green and elegant.
• Iris Silver Mist by Serge Lutens (1994): earthy, rooty and cold. For when you want the real thing.

How to wear iris

• Iris is subtle, so it works well in offices and close quarters.
• It suits cooler weather and crisp days especially well.
• Give it time on skin. The earthy, carrot-like opening often turns soft and powdery.
• If you find iris "too powdery", try one paired with woods or leather.

Who will love it

People who like quiet, elegant scents, fans of powdery or "clean make-up" smells, and anyone tired of loud, sweet perfume. Iris rewards patience. It may not shout, but it lingers beautifully.