Irises: Flower Types, Plant Varieties, How To Grow and Plant Care

Irises have been widely cultivated and admired for centuries, and this shows no sign of slowing down. Why should it? Irises are perennials which produce unique flowers, which mean different things to different cultures.

While you might think of irises being blue with yellow stripes, there are so many other colors that these fascinating plants produce. The Greeks even named the Iris after the goddess of the rainbow in honor of this. 

If you want to bring some new life and color into your garden, irises are a fantastic choice.

Their delicate appearance can put people off, as they can believe that these plants are tricky to look after, but nothing could be further from the truth. 

Read on to discover more about the iris’s history, how to grow them, and the different types you can get.

At a Glance: Iris Facts

The History Behind the Name

The iris is named after the Greek word for rainbow, as well as the Greek goddess of the rainbow, and many believe this comes from the sheer range of colors these flowers come in.

It’s also one of the few plants that shares its scientific and common name. It comes from the Iridaceae family of plants, and is a relatively large genus in its own right, encompassing around 300 different species.

Growing irises as ornamental plants is a practice dating back as far as 1469 BC in Egypt. 

King Thutmose III valued plants as much as gold, and when in Syria on a conquest, he ordered these plants to be brought home, where they were grown all over Egypt. They soon became symbolic of life, and life’s renewal.

Irises are also a concrete part of Europe’s history, especially during the Middle Ages, when it became the symbol of the fleur-de-lis

This symbol also became synonymous with the French monarchy, once King Clovis I converted to Christianity. 

There is also a lot of symbolism surrounding this gorgeous plant. To discover what this flower represents, click here.

How to Use Iris Flowers and Their Benefits

Medicinal Uses

While these plants are beautiful in their own right, they also have a number of medicinal uses. 

The roots have purgative properties, and can be used to treat lung ailments. Crushed iris roots help treat skin problems, while infusions of the root help relieve liver problems.

Iris root tea helps with digestive problems, kidney problems, and bladder disorders.

It’s worth mentioning that you should never self-medicate, especially when it comes to plants. It can go wrong very easily, and you can ingest the wrong amount, or even something that will exacerbate your problem. If in doubt, speak to your doctor.

Garden and Landscape Uses

Irises are great landscaping tools, and can transform any planting scheme into a rich and fantastic display. 

These plants will thrive in containers as well as in the ground, and look particularly beautiful on either side of an entryway, or somewhere you’ll pass every day. 

Wherever you choose to grow them, you can create a much more impactful display if you grow them in bigger numbers.

When thinking about what types of flowers you want to compliment or contrast irises with, they go well with a huge variety of different species, in almost endless combinations. 

You can grow them with taller plants such as gladioli,  foxgloves, and salvia. For shorter plants, why not try dianthus, violets, lobelia, or daffodils? 

These are just a few combinations to try, but the real fun begins when you start to experiment. 

Other Uses

The rhizomes are often used in making perfume and incense, as well as in cosmetics.

How to Recognize the Iris

Iris Flowers

The bloom of the iris, of course, is immediately recognizable, as it’s unique to the species. 

Every iris has a similar shape where it has standard and fall petals. Standard petals literally ‘stand’ upright, while the falls drape toward the earth. 

The size of these gorgeous blooms can range anywhere from 2 inches to 10 inches across, and you can also get dwarf varieties which have much more delicate, petite blooms.

Irises are often bicolored, or even tricolored, sometimes featuring stripes in the center of the fall petals of a darker or completely different color. Some irises can be different shades of the same color, while some wildly contrast. 

Iris Leaves

Iris leaves are often described as sword-like, as they are long and mostly end in a point. While they are a feature of themselves, unfortunately they aren’t evergreen. 

While they are usually light green, some varieties can even be variegated. 

Iris Seed Pods

Once the flowers have finished, they can produce seed pods, which have a very dry texture. These pods will split along the midrib to release the seeds. 

Iris Stems

Iris stems are green, and depending on the variety, can be knife-thin or fairly thick. Unlike geraniums, iris stems don’t have any fragrance.

Iris Roots

Depending on the variety, irises grow from rhizomes or bulbs.

Iris Types

If you’re interested in growing irises, the first thing to know is the different types you can get. This will mean that you’ll know exactly which kind is best for you and your garden, how to look after each plant, and what kind of maintenance it needs. 

Irises are perennial plants, and come in two types: irises which grow from bulbs, and irises which grow from rhizomes.

Bulb Irises

Bulb irises flower earlier than rhizome irises, and have flowers which grow in a more petite form. Most will go dormant after they put on their display until the following year. 

Iris hollandica ‘Dutch Iris’

One of the most widely-grown types of iris, the Dutch iris, or Iris hollandica is used for cut flower production, as these blooms last a long time. 

There have also been several hybrids created from the Dutch iris, including the Spanish iris. 

Iris reticulata ‘Reticulata Iris’

A much smaller iris, the iris reticulata produces very petite but striking flowers in hugely bright shades that will hold their own in any display. The plant itself, likewise, doesn’t get very tall.

They’re commonly grown in pots, and they’re also known as netted iris, because the bulb grows a fibrous texture similar to a net. 

Rhizome Irises

If you’re picturing plants which grow a lot taller, the rhizome iris is for you. They can grow to a maximum height of 3 feet, depending on the type.

They also bloom later in the year, from mid-spring into the early days of summer. While the rhizome is under the soil just like the bulb, this iris creates new shoots more readily.

Rhizome irises can be divided into three groups according to the flower’s appearance: bearded, beardless, and crested.

Bearded Iris Flowers

Bearded irises are by far the most blousy looking of all types, having a ruffled appearance. They are very easy to grow, and come in many colors and heights.

Bearded irises are also recognizable by the tiny hairs that sit on each fall petal. These hairs act as an arrow for the pollinators, pointing toward the center of the flower.

You might also hear bearded irises referred to as pogon. Bearded irises can be further divided into five types ranging in size, from miniature or dwarf types of irises, to the tallest which are the border bearded irises. 

Beardless Iris Flowers

Like the name suggests, beardless irises don’t have the tiny hairs to mark the direction the pollinators need to go in. 

Instead, they have what’s called ‘signals’ or flashes of yellow or orange to point the way. These always form on the fall petals.

Beardless irises are also known as apogon. While they don’t have as much of an elaborate appearance, beardless irises adapt better to different conditions, and you can grow them in many types of soil and types of light.

Some beardless iris examples include Siberian Iris, Japanese Iris, and the wild iris, also known as the Species Iris. 

Crested Iris Flowers

Crested iris blooms have neither beards nor signals. The way they attract pollinators is through a white and or yellow crest, which you can spot from afar. 

The crest itself is referred to as a cockscomb because of its shape. 

Cultivars to Grow in Your Own Garden

Fancy growing your own irises? Here are just a few of the stunning options available. 

Iris germanica ‘Carnival Time’ 

Reminiscent of the bright colors of a carnival, or a bold and beautiful sunset, ‘Carnival Time’ is a fantastic bearded iris. It reaches up to 3 feet tall, and requires full sun to produce large flowers in a warm amber, which fade to a deep red. 

Iris hollandica Dutch Iris ‘Lion King’

Just like ‘Carnival Time’ the ‘Lion King’ iris needs full sun in order to get the very best out of this plant. It flowers from May until June, and reaches a smaller height of just under 2 feet tall. 

Once established, this iris will produce huge copper blooms for decades to come. 

Iris hollandica  Dutch Iris ‘Alaska’ 

If you want to add some elegance to your planting scheme, ‘Alaska’ is a great option, producing beautiful white flowers with a stripe of yellow along the fall petals. It flowers from May until June, and prefers full sun.

It’s also a cultivar that’s not fussy about the type of soil it grows in, as long as it drains well. 

‘Alaska’ can grow up to just shy of 2 feet tall, and is a perfect option for a cutting garden. 

Iris sibirica ‘Paprikash’

This Siberian iris produces captivating blooms in shades of burgundy and lilac, with fabulous gold-tinged fall petals. It’s a good variety that will produce more blooms year after year, and will eventually spread a little. 

It can also grow up to 2 ½ feet tall, so long as it gets full sun. Like ‘Alaska’ it largely doesn’t matter what soil you grow it in, provided there is no risk of root rot. 

‘Paprikash’ is very easy to grow, and you’ll only have to wait until May to see these fabulous flowers at their best. 

Iris germanica ‘Nightfall’ 

If you’d prefer a more ‘traditional’ color when it comes to irises, ‘Nightfall’ produces flowers in a royal purple, which deepens to plum and nearly black in the fall petals. 

‘Nightfall’ is a very hardy variety, and can grow in both full sun and partial shade. The plant itself grows just over 2 feet tall, and prefers moist soil. It will also naturalize well, producing more plants. 

How to Grow Irises

Irises are very easy to grow. They do have a few requirements, and this can depend on the type of iris you choose, so it’s worth getting to know your garden, what type of soil you have, and what conditions you have before you start planting. 

Irises also have the benefit of being generally resistant to deer and rabbits, but you may need to protect young shoots, as these seem to be more sought after!

Where to Grow

Most irises want full sun in order to develop the brightest colors and the deepest shades they are capable of. 

As they are rhizomes and bulbs, they are mostly vulnerable to root rot, so most types will need well-draining soil to prevent this.

Like with most plants, a well-ventilated area can help stop disease from taking hold of your plants. Better air circulation means there’s less of a chance of your plants falling prey to disease. 

Planting Your Irises

While when you think of bulb planting, you might be tempted to plant iris rhizomes and bulbs deep into the ground, this can actually prevent them from flowering.

Instead, irises need to be planted a little closer to the surface. The top part of the rhizome needs to be exposed to the sun, while the bottom part needs to be underground.

If you’re planting more than one iris – and this will make for a far better display – you’ll need to put around 18 inches of space between them. 

You should plant them well before the risk of frost sets in, from September onwards. 

This ensures that the plants have enough time to establish their roots within the soil before the cold temperatures take hold. Otherwise, this can damage the iris buds.

Feeding Your Irises

Irises benefit from a good fertilizer, though be careful not to get any on the rhizomes or the bulbs, as this can burn them! 

If you have soil that doesn’t drain well, you can help by putting fresh compost around 10 inches deep into the soil, where you’re going to plant the irises. 

When it comes to feeding irises, they only require a fairly light fertilizer in early spring, and another feed a month after the flowers have finished. 

Dividing Your Irises

Irises spread fairly well, but you’ll occasionally need to divide them. Why? They can get crowded – but this only happens around 3 to 5 years after you’ve planted them. 

If you don’t divide them, you will eventually risk losing the plants altogether.

Wait until the flowering season is over, in the late days of summer or early autumn.

You’ll need to cut the leaves to a third of their full height, and dig up the rhizomes. Get rid of any damaged rhizomes, any that have rotten, and any that are very old from the clump.

Divide the rhizomes into groups of one or two fans at most, and replant, spacing them apart normally.

Deadheading Your Irises

While not everyone deadheads their irises, you can do so in order to encourage repeat flowering. 

Cut both the flowers and the stalks that have finished, and this will signal to the iris that it needs to produce more flowers.

Iris Pests and Diseases

For the most part, irises will do fine on their own. However, you may occasionally get some pests and diseases that will try to take hold.

Of the pests, the worst by far when it comes to irises are the iris borer caterpillars. These bad guys eat the rhizomes and the leaves, which can also leave the irises vulnerable to rot.

Prevent these caterpillars from feasting on your irises by removing yellowing or dying foliage from the plant. If you see signs of the iris borers, you can also use insecticides, but this is a last resort, as it also kills beneficial insects living in the soil.

Other pests include aphids, iris weevils, snails, slugs, and bud moths.

When it comes to diseases, bacterial soft rot is notorious. It makes what would be strong and healthy rhizomes into mush. 

Crown rot is a similar disease, but it has a much worse smell. It will also make the base of the leaves have small spots.

Again, to prevent these diseases, remove any yellowing leaves and any dead leaves from the plant and the surface of the soil. 

Other diseases that can kill an iris include fungal leaf spot, fungal root crown, and bacterial leaf blight.

Iris Flowers Frequently Asked Questions

What do Iris Flowers Represent?

Iris flowers have a lot of symbolism behind each bloom, and a rich history. Because there are so many colors to choose from, the symbolism behind the iris can be multi-layered. 

To discover the meaning behind each flower color, click through to the link above.

Bicolored blooms take on the meaning of both colors. 

When given as a gift, purple and white irises symbolize someone exceedingly special who stands out among others, someone who is wise and genuine. 

Yellow and blue irises represent hope and faith. If you give someone a yellow and blue iris, this is a message saying that you’re grateful to have this person in your life. 

Your connection with them gives you a lot of hope for the future, and you’re sure your relationship will last a lifetime.

Orange and yellow irises are a sign of happiness and positivity, as well as prosperity and a passion for life. 

If you give someone an orange and yellow iris, you’re telling them that you think they are worth all the gold in the world, and that your connection brings you a lot of happiness. 

Why do Iris Flowers Change Color?

Irises are not known to change color completely. However, the color can fade, and this is usually the plant telling you that the conditions are not ideal. 

An iris losing its color indicates that they are getting too much or too little sun, the temperature is too hot or too cold, or the soil pH is simply not right for the variety. 

Can an Iris Flower More than Once?

It depends on the variety. Some irises are classified as remontant varieties, which means they rebloom in summer or autumn after the first flush of flowers in early summer. 

They are rebloomers, cycle rebloomers, all-season rebloomers, and repeaters.

Rebloomers produce flowers twice or more per year. Cycle rebloomers bloom in spring, and again in fall, without producing flowers in the summer.

Repeater blooming irises flower soon after the spring flush of flowers have finished, and all-season bloomers will produce flowers throughout the season, although it will be somewhat sporadic. 

What do Iris Flowers Attract?

Iris flowers attract a lot of beneficial insects, including bees, butterflies, hummingbirds, and hover flies. The last of which helps keep pest levels down. 

Can Irises Grow in Shade?

Most irises thrive in full sun, but some will tolerate partial shade. The most tolerant of darker conditions is the stinking iris, or Iris foetidissima, which, like the name suggests, doesn’t smell pleasant! 

You can even grow the stinking iris in full shade. It does prefer a drier soil if possible, which may be a tricky combination to get right, but it is perfect for woodland areas.

Are Iris Plants Toxic? 

Irises are quite poisonous if ingested. These plants contain toxins such as irisine, iridin, and irisin. These toxins cause skin irritation, so if you are tending to your irises, you should always wear gloves.

If eaten, irises can cause vomiting, diarrhea, stomach pain, fever, and feeling generally unwell. Not recommended!

Conclusion 

When it comes to ornamental plants, some of the most showy and unforgettable flowers are produced by irises. 

While they can be a little vulnerable to pests and diseases, so long as you choose the right type for your garden, they will provide you with fantastic color year after year. 

There’s a variety for every garden and planting theme, with so many colors to choose from in varying heights, there are endless possibilities. Most irises will also thrive in containers, which is especially useful if your soil is poor or if you don’t have any!

Irises are a sure-fire way to breathe new life and color into your own slice of paradise, whatever theme you might have, whether that’s a more tropical planting scheme, a traditional cottage garden, or you’re simply looking for something unusual that will happily grow in pots in your yard. 

However you choose to decorate your own outside space, irises are the perfect option to add a sense of theater into your space, all the while not demanding too much attention or time from you.

The flowers themselves are guaranteed to halt you in your tracks, as they are spectacular in their own right. 

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