purple and blue iris flowers

How To Grow Care For Irises

There are very few gardeners in the world, no matter how inexperienced, that do not know about the iris flower. They are among the most diverse flowering plants when it comes to colors and growing needs. At the same time, the iris is easily distinguishable – their leaves are akin to swords and their flowers have six drooping lobes.

Growing an iris flower is slightly complicated but the complications only last till it matures. After that, it is simple to maintain and has very few needs. There are three main categories of iris flowers: “crested”, “beardless”, and “bearded”. The bearded variant is the one that you will encounter since they are also the easiest to handle. These flowers attract hummingbirds and other pollinators.

Read more: These 22 perennials will thrive in your garden for decades

Growing Iris

The bearded iris is preferably planted at the height of spring. Half of the variants bloom in the first year itself, while some others can take up to another few months. The “bearded” name is given to the variants that have soft hairs along the center of the petals of the flowers. Most bearded variants are also remontant – that is they bloom twice, once in early summer and another during late summer.

Here are some quick facts about the colorful flowering plant:

  • Latin name: Iris/ Iris germanica (bearded variant)
  • Other names: Flags, junos
  • Native to: Europe, Asia
  • Invasiveness: Slightly. Yellow Iris is particularly invasive.
  • Tenderness: Herbaceous perennial
  • Sun: Full Sun.
  • Water: Occasional watering.
  • Soil: Well-drained, average.
  • Hardiness zone: Zones 3 through 9
  • When to plant: Spring
  • Spacing: 12” to 24”.
  • Plant height: 12” to 40”.
  • Bloom period: Spring
  • Time to maturity: 1 to 2 years.
  • Container friendly: Yes.
  • Fertilizer: 10-10-10/6-10-10
  • Toxicity: Toxic to cats and dogs.
  • Deer resistant: Yes.
  • Pest resistant: No.

The bearded iris flowers have further sub-categories. They can be tall, intermediate, short, miniature, or short. Although the main difference between them is their size, some also have different blooming times. If you are undecided on which iris to grow, then you may want to select from famous award recipients.

These flowering plants are famous for their durable nature. They can survive extreme temperatures, provided their soil does not let any water stagnate. However, some of the variants, because of their height, can be susceptible to wind damage.

Iris love the sun. So pick a sunny spot in your garden to plant these flowers. It is very important to avoid burying the rhizome completely. However, take care to bury all the roots. Just leave the rhizome a bit above ground since, otherwise, it can result in root rot.


Iris do like moisture, however, it is not essential for them. They are naturally drought-resistant plants. So a good measure would be to water them when the soil’s top 2” feels dry to the touch. However, during extended periods of drought, water them regularly since even drought-resistant plants can benefit from water.


To unleash the full potential of the iris plant, make sure it receives the full sun. It can survive in areas with shade, but there will be fewer blooms and the plant has a higher likelihood of getting diseased.


The iris plant prefers gravelly or sandy soil and hates heavy, clay soil when it is growing. These plants can improve drainage in heavy, compacted soil. Nevertheless, it is absolutely vital that the soil is good at draining excess water.


During spring, feed it a 6-10-10 low nitrogen fertilizer by placing it around the plant. A nitrogen overdose will increase the plant’s foliage while decreasing its blooms. Another excellent fertilizer for the plant is bone meal.

Iris prefer not to be mulched, so avoid any kind of mulching.


The yellow iris (iris pseudacorus) is exceptionally fast at natural propagation and is as invasive as cat-tails in wetland areas. Generally, iris rhizomes are naturally easy when it comes to propagation, so there is a slight risk of them turning invasive.

Growing Iris in containers

The iris plant can be grown in containers. But make sure they have a minimum width of 12”. You can use soil-free, loose, potting mixes. Similar to growing them on the ground, ensure that the rhizomes remain exposed. Also, take care to not give them too much water. Container-grown irises may need to be divided and transplanted more often than the specimens grown outside.

Care & tips

Pinch off withered or faded flowers since this can encourage more blooming. After about every 4 to 5 years, dig up the plants, divide and replant them to remove diseased roots and damage done by iris borer pests. This will also keep the plants vigorous.

As winter approaches, time back the plants’ foliage to approximately 6”. This will give a tidier appearance as well as reduce the chances of fungal disease. Do not compost any of the foliage. Also, check for root rot or iris borer damage a few weeks before winter kicks in fully. Remove all damaged or diseased sections and replant the root sections that remain.

Common problems

The iris plant’s greatest enemy is possibly the iris borer. It is a type of caterpillar that digs into the iris and feeds into the rhizome from the inside. Bacterial rots also set in because of the feeding tunnels. After frost passes, check and remove all leaves of the iris plant to eliminate the eggs. If there are infected rhizomes, remove the infested, soft portions. Then, the remaining pieces can be replanted.

Other diseases include fungal leaf spots, mottling of leaves, and bacterial soft rot. Remove and destroy the parts that are affected. Do not compost them.

Root rot can cause leaves to turn brown or yellow, and the plant to slowly fall over. Some tall variants of the iris plant can grow to 40”, in which case staking is recommended to help them stay upright. Fungal or bacterial infections can result in spotted leaves.

Propagating Iris

Iris propagation requires the plant to be divided. During summer, dig up the rhizomes can clean off loose soil. Then carefully divide them into sections by pulling or cutting. Keep a foliage fan in each section. Before replanting them, check for any damage closely. New growth is likely to sprout later in the summer. Do this every 3 to 5 years.

Iris plants are grown from seeds by professionals usually. However, it is possible to do so. Simply collect a cluster of seeds and plant them about a quarter-inch deep. However, the results may not be what you expect even if they grow up.

The History Of The Iris Plant

The plant has a long and varied history. The earliest mentions of the flower are in Ancient Greece. There, Goddess Iris and her flower stood for the rainbow and the bridge between earth and heaven. As such, the flowers were planted at women’s graves in hopes that the Goddess will guide them to the land of the dead.

In Ancient Egypt, kings hailed the flower for its beauty. In the Middle Ages, the flower became a proud symbol of the monarchy in French where it exists today in the fleur-de-lis.

Uses for Iris

In the garden, the plant is usually planted as colorful additions to perennial borders. However, in earlier times, they were used as a source of perfumes and medicines.

Iris are highly toxic to all pets if ingested, especially the bulbs. It will cause distress to humans as well.

The iris plant is a very common and easy to grow plant that all beginners can take on. Honestly, once you start growing them, you won’t ever get bored because of the different varieties.

Mayukh Saha
Freelance Writer
Mayukh is a Content Marketer and Social Media Manager with over 5 years of experience in the industry. Mayukh believes in the power of content; how it can positively impact lives, scale businesses and touch people. In his spare time Mayukh likes to read about latest tech trends and loves to travel in the nature. You can reach him at [email protected].