Understanding The 2 Different Types of Iris Flowers

Named after the Greek goddess of the rainbow, the iris is a flower of immense beauty and diversity. This guide provides a snapshot of its main classifications and highlights popular types and varieties. 

We will explore their unique characteristics, the rich symbolism behind their colours, and offer insights into enjoying these sophisticated blooms. This is a resource for understanding the captivating world of irises and choosing the perfect one for any occasion.

Understanding the Main Classifications of Iris

With over 300 species and thousands upon thousands of cultivars, the Iris genus is one of the most varied and beloved in the floral kingdom. Navigating this vast family can seem daunting, but thankfully, botanists and gardeners have a simple system to categorise them. 

The primary classification is based on their root structure, a fundamental difference that dictates not only how they look but also how they grow and what they need to thrive. Understanding this difference is the first step to appreciating the unique charm of each iris type. The two main groups are rhizomatous irises, which grow from a creeping rootstock, and bulbous irises, which sprout from a classic bulb.

Irises are a great addition to any flower bouquet. They are vibrant and offer plenty of variety.

1. Rhizomatous Irises

The vast majority of iris types, including many of the most famous and spectacular garden varieties, are rhizomatous. A rhizome is a specialised, fleshy stem that grows horizontally, usually just at or slightly below the surface of the soil. Think of it as a living, underground highway for the plant. It acts as a crucial storage organ, holding reserves of food and water that allow the plant to survive periods of dormancy and fuel its spring growth.

New growth, in the form of leaf fans and flower stalks, sprouts upwards from nodes along the rhizome, while roots anchor it firmly from below. This creeping growth habit means that a single rhizome planted today can expand over several years into a magnificent and dense clump, producing more and more flowers each season. This group is incredibly diverse and is further divided into two famous sub-groups: Bearded Irises and Beardless Irises.

2. Bulbous Irises

In contrast to the sprawling rhizomes, bulbous irises grow from a true bulb. A bulb is a neat, compact, underground package, much like the familiar onion, tulip, or daffodil bulb. It contains the plant's entire life code in an embryonic form, protected and nourished by layers of fleshy scales. This structure is a self-contained survival kit, providing all the energy the plant needs to sprout and flower.

Bulbous irises are typically smaller and more delicate in appearance than their rhizomatous cousins. They are often planted in autumn, bloom beautifully in the spring, and then enter a period of dormancy during the summer heat after their foliage dies back. 

Their tidy, self-contained nature makes them excellent for planting in neat groups and, most importantly, for the global cut flower trade. The Dutch Iris, a florist's absolute staple, is the most prominent and commercially important member of this group. You can add it to your flower subscription and you can expect to be pleasantly surprised.

Bearded Irises

When most people close their eyes and picture an iris, they are almost certainly thinking of a magnificent Bearded Iris (Iris germanica). 

These are the quintessential, spectacular garden irises, celebrated across the world for their enormous, ruffled flowers, an almost unbelievable range of colours, and the distinct, fuzzy line on their lower petals that gives them their name. 

In temperate climates, they are the undisputed stars of the late spring garden, commanding attention with their majestic presence, intricate patterns, and sometimes, a sweet, grape-like fragrance.

Characteristics of Bearded Irises

The structure of a Bearded Iris flower is a true work of natural art. Each bloom consists of six petals, which botanists call "tepals." There are three upright petals called "standards," which often arch together to form a beautiful dome. Below them are three gracefully drooping petals known as "falls." Running right down the centre of each fall is the "beard," a thick, soft strip of dense hairs that looks like a tiny, plush caterpillar.

This feature is not just for show; it serves as a crucial nectar guide, showing bees and other pollinators the direct path to their sweet reward.

The foliage is equally distinctive, with broad, sword-like leaves that grow in a flat, fan-shaped clump. The leaves are typically a soft grey-green colour, providing a beautiful structural contrast to the vibrant flowers.

To flourish, Bearded Irises have strict requirements: they demand at least six hours of direct sunlight per day and, most critically, excellent drainage. Their rhizomes must not sit in waterlogged soil, as this leads to rot.

Popular Varieties and Their Colours

The colour palette of Bearded Irises is nearly limitless, a testament to over a century of intensive and passionate hybridising. They are available in every colour and combination imaginable, except for a true, fire-engine red.

• 'Immortality': A world-famous and beloved variety, 'Immortality' is prized for its pristine, pure white flowers with just a hint of a light yellow beard. It is also a "rebloomer," meaning it can flower again later in the season in ideal climates, making it a garden favourite for its classic, elegant look.
• 'Celebration Song': This variety is a party in a flower. It is a stunning bicolour iris featuring soft, apricot-pink standards that sit atop rich, lavender-blue falls. The contrast is cheerful and vibrant, creating a lively and joyful display in any setting.
• 'Dusky Challenger': A titan among irises and a winner of the prestigious Dykes Medal, this variety boasts enormous, heavily ruffled flowers in a deep, velvety shade of dark purple-black. It is the definition of drama and sophistication, making an unforgettable statement wherever it is seen.

Beardless Irises

As their straightforward name suggests, Beardless Irises are rhizomatous irises that do not have the fuzzy beard on their falls. This is an incredibly large and diverse group of plants, often characterised by a more graceful and understated elegance compared to their bearded cousins.

Their flowers can be just as beautiful, but they typically have a sleeker, flatter, and more refined form. Many species within this group are more adaptable to moist soils and varied climates, making them among the flowers that bloom all year in SG.

Siberian Irises (Iris sibirica)

Siberian Irises are the ballerinas of the iris world. They embody grace and poise, producing smaller, more delicate flowers on slender yet remarkably strong stems that rise high above attractive clumps of bright green, grass-like foliage.

Their beauty lies in their simplicity and structure. The flowers are typically found in intense shades of blue, violet, and pristine white, often decorated with intricate yellow or white markings, called signals, at the base of the falls. Unlike Bearded Irises, they appreciate consistently moist soil and can even tolerate partial shade.

Their elegant form and sturdy stems make them a wonderful and long-lasting cut flower, adding a touch of sophisticated wildflower charm to any bouquet.

Japanese Irises (Iris ensata)

For sheer flower size and a sense of pure luxury, the Japanese Iris is unrivalled. These irises produce enormous, flattened blooms that can measure up to an astonishing 25 cm across, resembling a floating platter of ruffled silk. Often called "dinner-plate" irises, their falls are exceptionally large and hang downwards, creating a dramatic, opulent look.

They bloom later in the season than most other irises and come in a palette of rich, regal shades of purple, royal blue, delicate pink, and pure white, frequently adorned with exquisite veining and patterns. Japanese Irises are true water lovers, traditionally grown in the marshy conditions of rice paddies in Japan.

This makes them a potential, though challenging, candidate for specialised water gardens or pond edges in Singapore, provided their specific needs for acidic, moist soil can be met.

Louisiana Irises (Iris series Hexagonae)

The Louisiana Iris group is a hidden gem and perhaps the most promising type for ambitious gardeners in Singapore. This group comprises five distinct species native to the hot and humid swamplands of the southeastern United States, particularly the state of Louisiana.

As a result, they are naturally adapted to the very conditions that cause other irises to fail: intense heat, high humidity, and wet soils. Their flowers are large, open, and feature a beautifully relaxed form.

Their colour range is particularly exciting and unique in the iris world, including vibrant shades of terra cotta, rusty red, and coppery-brown, which are very rare in other iris types. For anyone determined to grow irises in a tropical climate, the Louisiana Iris is the top choice to investigate.

Dutch Irises

When you walk into a florist in Singapore and buy a bouquet containing irises, you are most likely purchasing a Dutch Iris (Iris hollandica). These are bulbous irises that were specifically and expertly hybridised in the Netherlands to be the perfect cut flower.

They are valued by florists and flower lovers everywhere for their reliability, long vase life, classic beauty, and straight, sturdy stems, making them a cornerstone of the global floral industry.

The Distinctive Look of Dutch Irises

Dutch Irises possess a sleek and sophisticated silhouette that is instantly recognisable. The flowers are smaller and less frilly than those of the Bearded Iris, with a poised and elegant structure that speaks of modern refinement.

They grow on long, straight, and slender stems, which is the ideal characteristic for floral design, allowing them to add height and clean lines to an arrangement. The classic Dutch Iris flower features three upright standards, which are often narrower than the falls, and three smaller, gracefully arching falls.

Their colour palette is focused and strong, with the most popular and recognisable shades being a deep, royal blue, a brilliant sunshine yellow, a pure, clean white, and a rich, velvety violet-purple.

Why Dutch Irises Thrive in Bouquets

Dutch Irises are bred for performance from field to vase. Their long, sturdy stems make them incredibly easy for florists to work with and allow them to add height and structure to both simple and complex arrangements.

Once cut, they have an impressive vase life, often looking fresh and beautiful for five to seven days with proper care. To get the most out of your cut Dutch Irises, be sure to trim about 2-3 cm off the stems at an angle before placing them in a clean vase with fresh water and the provided flower food.

Their elegant shape and vibrant, clear colours make them incredibly versatile. They look stunning on their own in a simple glass vase or serve as a striking feature flower in a mixed seasonal bouquet.

The Meaning and Symbolism of Iris Colours

Beyond their undeniable physical beauty, irises carry a deep well of symbolism, largely connected to their historic name and their glorious spectrum of colours.

Named after the Greek goddess Iris, who personified the rainbow and acted as a swift messenger linking the heavens and earth, the iris flower has long been a symbol of communication, divine messages, and connection.

The general meaning of the flower is one of wisdom, hope, trust, and valour, but each specific colour tells its own unique and beautiful story.

Purple Iris: Royalty and Wisdom

For centuries, purple has been the colour of royalty, nobility, power, and wealth. This is because purple dye was historically rare and expensive to produce. A purple iris, with its deep and majestic hue, carries these powerful connotations forward.

Purple flowers symbolise wisdom, respect, dignity, and admiration. Gifting a bouquet of deep purple irises is a wonderful way to compliment someone's achievements, to show a deep and respectful form of admiration, or to honour a person you look up to.

Blue Iris: Faith and Hope

Blue is the colour of the sky and the sea, evoking feelings of tranquillity, faith, and hope. A blue iris speaks of steadfastness, serenity, and a deep, abiding trust.

It is a calming and thoughtful flower, making it perfect for conveying a message of sincere hope for the future or expressing unwavering faith in a person, a cause, or a relationship. Its serene presence makes it a beautiful and meaningful gesture for almost any occasion, offering a sense of peace and reassurance.

Yellow Iris: Passion and Pride

Bright, sunny, and cheerful, the yellow iris is bursting with vibrant energy. It is a powerful symbol of passion, pride, and overwhelming joy. While some other yellow flowers can sometimes carry a faint meaning of jealousy, the yellow iris is overwhelmingly positive and celebratory.

It is an excellent choice for celebrating a friend's success, congratulating someone on a new venture, conveying your pride in their accomplishments, or simply sending a brilliant burst of happiness to brighten their day.

White Iris: Purity and Innocence

Like many classic white flowers, the white iris is a potent symbol of purity, innocence, reverence, and elegance. Its clean, flawless, and unblemished petals convey a sense of sincerity and a fresh start.

This makes white irises an incredibly popular and meaningful choice for bridal bouquets and wedding decorations, where they symbolise the pure love and new beginning of the couple.

They are also used to convey sympathy and heartfelt condolences, offering a message of peace, spirituality, and hope in difficult times.

Conclusion On The Different Types of Iris Flowers

In summary, the world of irises is wonderfully diverse, primarily categorised into the grand Bearded Iris, the sleek Beardless varieties like the Siberian and Japanese, and the ever-popular Dutch Iris found in florist shops.

Each type offers a unique aesthetic, from the ruffled opulence of the Bearded Iris to the graceful simplicity of its cousins. The rich symbolism tied to each colour, from royal purple to hopeful blue, allows for deeply personal and meaningful gift-giving.

While growing certain types in Singapore's climate presents a significant challenge, their stunning beauty is readily accessible in expertly crafted floral arrangements. Ultimately, the iris offers a perfect bloom for every message and home, solidifying its status as a timeless flower of distinction. Express your care with a bouquet. A flower delivery service is a convenient way of sending your message.

Contact us for enquiries about irises and other flowers in Singapore. We’d love to talk to you!

Frequently Asked Questions About The Types Of Iris Flower 

What are the 3 types of iris?

The three main horticultural classifications of irises are Bearded Irises, Beardless Irises, and Bulbous Irises. Bearded Irises are famous for the fuzzy "beard" on their lower petals and grow from a thick root called a rhizome. Beardless Irises also grow from rhizomes but lack this fuzzy feature and include diverse species like Siberian and Japanese irises. Bulbous Irises, such as the common Dutch Iris, grow from a true bulb rather than a rhizome.

What is the most common type of iris?

The Bearded Iris (Iris germanica) is arguably the most common and widely recognised type grown in gardens around the world, especially in temperate climates. However, for the floral industry and for customers in Singapore, the Dutch Iris is the most common type. It is the iris you are most likely to find in a florist shop worldwide due to its excellent qualities as a long-lasting cut flower.

What is the most beautiful iris flower?

Beauty is truly in the eye of the beholder, as each iris type offers a unique and distinct charm. Many people are captivated by the large, ruffled, and incredibly colourful blooms of the Bearded Iris. Others prefer the sophisticated, orchid-like elegance of the Japanese Iris, with its massive, silken petals. Still others favour the classic, poised shape of a deep blue or pure white Dutch Iris. The best way to decide is to explore the different varieties and discover your personal favourite.

How many different types of iris flowers are there?

The Iris genus is incredibly vast, containing between 250 to over 300 different natural species. When you add the thousands upon thousands of registered hybrids and cultivars that have been developed by passionate breeders over many decades, the number of distinct iris flowers becomes immense. This offers a nearly endless variety of colours, forms, sizes, and patterns for flower lovers to enjoy.

What do iris flowers symbolise?

Overall, the iris flower symbolises wisdom, hope, trust, and valour. It was named after the Greek goddess of the rainbow, Iris, who was believed to deliver messages from the gods to mortals. The specific meaning can also change with colour: purple symbolises royalty and wisdom, blue represents faith and hope, yellow conveys passion and pride, and white stands for purity and innocence.

Which iris blooms the longest?

In a garden setting in temperate climates, some specially bred "reblooming" or "remontant" Bearded Iris varieties are known to flower more than once a season, effectively extending their bloom period. However, when it comes to longevity as a cut flower in a vase, the Dutch Iris is the undisputed champion. They are specifically cultivated for a long vase life and can easily last up to a week or more with proper care, which is why they are a favourite among florists.

From our Singapore florist: Drawn to the iris? Browse our fresh hand bouquets for striking blooms delivered across Singapore.

Jim Ng

Owner of Singapore Florist

Jim Ng is the owner of Singapore Florist, the boutique flower studio first opened in 1987 by its founding family. Jim and his team acquired Singapore Florist from the original owners with one promise: keep the craft, keep the customer relationships, and modernise everything else. Today the studio works out of Eunos Techpark, ships fresh stems islandwide, and has grown its review base past 202 verified Google reviews.

This article is part of an ongoing, well-researched flower-care library written by the Singapore Florist team, drawing on nearly four decades of hands-on bouquet design, daily delivery experience, and direct relationships with growers across Asia. If you spot anything we have missed or have a specific flower question, WhatsApp us directly and we will weave the answer into a future post.