2022 | How to Care for Iris Ensata (Japanese Iris)

Iris Ensata plants are commonly known as the Japanese Iris and Japanese Water Iris, grown for their beautiful flowers, belong to the Iridaceae family of flowering plants. They are native to Japan but are widely grown in many other Asian countries, including, China, Korea, and Russia for their beautiful flowers. Its small size and easy to grow nature, make it one of the perfect plants for indoor decoration and outdoor gardens.

Japanese Iris can grow up to 80 cm (30 to 31 inches) tall. They cover a small space, so you can easily grow them in the indoor planters and pots. Japanese Iris has strap-shaped leaves that surround the stem. The flowers are originally purple but turn into yellow during the fall. These flowers are mostly seen during the midsummer. Apart from their original purple color, there are many other different colored hybrids or Japanese Iris that you can cultivate to get a different color.

Many varieties of Japanese Iris have won the Royal Horticultural Society’s Award of Garden Merit for their beauty and easy to grow nature. The Japanese Iris is also considered a very ancient Japanese flowering plant species, that was introduced in many gardens all around the world during the 1900s. The Japanese Iris is also linked with many traditions, customs of Japanese culture.

Best Varieties of Japanese Iris

There are a lot of beautiful varieties and cultivars of Japanese Iris that are grown worldwide. More than 15 varieties of Japanese Iris have won the Award of Garden Merits from the Royal Horticultural Society. These varieties are also one of the most beautiful and most grown varieties of Japanese Iris as well. Below I have listed some of the best varieties of the Japanese and their special characteristics

Aldridge Visitor:

This unique variety of Japanese Iris has won the Award of Garden Merits from the Royal Horticultural Society for its beautiful bloom and easy to grow nature. Their flowers are dark purple and have dark green leaves. They can grow up to 30 inches tall and can cover almost the same area. They need moist, slightly acidic humus-rich soil and full sun to thrive.

Alpine Majesty:

This is a cultivar of Japanese Iris, grown for its beautiful flower. The Alpine Majesty has also won the Award of Garden Merit from the Royal Horticultural Society. This variety is slightly bigger than most of the other Japanese Iris plant varieties. It can reach up to 120 centimeters or 47 inches. They take almost 2 years to reach their maximum height. Their bloom occurs in midsummer and they produce beautiful white flowers. They like the marshy, acidic soil and need more water to grow and thrive.

Hue and Cry:

Hue and Cry is a variety of Japanese Iris, also known as Japanese Beardless Iris. They are well-known for their iconic purple to blue flowers. They can grow up to 36 inches tall. They bloom during late spring to midsummer. They need a clay type of soil that is damp all the time and can trap water and create a marshy environment. The plant needs full sun to partial shade depending upon the season.

The Great Mogul:

The Great Mogul is a cultivar of Japanese Iris plants that has also won the Award of Garden Merits from the Royal Horticultural Society. This variety of Japanese Iris is named after the Mogul emperor, Genghis khan. This variety produces dark purple to bluish flowers during the late spring to mid-summer. These flowers have three large petals that surround the three inner and small petals. They like marshy, moist, and damp soil that is slightly acidic. They need proper water and full sunlight to thrive.

Southern Son:

The Southern Son is also a variety of Japanese Iris that has won the Award of Garden Merits from the Royal Horticultural Society. They produce beautiful bluish flowers that turn into purple during the midsummer days. Their leaves are swords-like and dark green. They can reach up to 30 inches in height. They are mostly grown in the moist, damp, marshy, and acidic soil. They do not like dry conditions. Proper watering and full sunlight can help you grow them easily.

Growing Conditions and Requirements

Their natural habitat is a cool, marshy environment with a soil that has low pH (is acidic). They are also capable of surviving very cold temperatures, even below zero. They are mostly propagated during the fall season. There are different variants of the Japanese Iris that are cultivated in different areas, most of these variants are identified with the help of different colors of their flowers.

They do not like well-draining soil, they like a soil that traps the water and remains damp. They grow very well in a boggy area and places near the water reservoirs, ponds, and rivers. In the pots and gardens, you will have to make sure that they get more water.

Below are the details about the growing conditions and requirements:

Water Requirements

Japanese Iris likes to be grown in boggy places meaning that they need more water than most of the plants. They do not like the soil to be dry, keeping it wet will encourage the fast growth of your Japanese Iris. You can follow the guidelines below to properly water them.

● Before planting them into the soil, you will have to water your potting soil. Watering the soil and keeping it moist for a few days before planting will create a perfect marshy environment in pots and gardens as well.

● Once you have planted pots or gardens, you need to water them once every two days. This frequent watering will help you keep the soil wet and damp. Do not let the soil dry, this is extremely harmful and can kill the young plants.

● Plants in the pots will need more water, then the plants that are directly planted in the soil. When watering them, you need to make sure that water reaches the bottom of the pot.

● Most of the experts advise that you should add some vinegar in the water to make it slightly acidic, (Japanese Iris need water with low pH). This type of water can be used for the plants in pots and the plants that are in gardens as well.

You can create a proper watering schedule based on age, height, season, and geographical factors.

Lighting Requirements

They do not like to be under the shade during the cool days, while in the hot summer days they need cover or shade. They are mostly grown outdoors, where they get full and direct sunlight.  But you can also grow them indoors, you just need to keep them somewhere they can get enough light. If you have a window that is facing east, that is the best place to keep them.

Low light exposure is not good for their proper growth, this can stop the growth of the plant and will also impact the size of the plant. Plants that are grown in low light cannot reach their potential height, and they also take more time to grow. You can also plant them under the shade of other trees in your garden.

Temperature Requirements

They like to be grown in slightly cold environments, but they can also be grown in hot areas as well. You can grow them in USDA hardiness zones between 4 to 9. You must plant them in areas where the temperature remains below 90 F. In extremely hot areas, they will need protection from the heat, so you will have to keep them indoors.

They can easily grow in areas where temperatures can go below zero. In Japan, they are mostly grown in extremely cold areas, where temperature can go as low as 0 F. They can also survive the frost conditions. Frost can damage their foliage but they do not die and regrow during the spring.

Japanese Iris plants thrive when the temperatures are between 20 F to 70 F. You can protect them from both extremely cold and extremely hot temperatures by keeping them indoors or covering them so that they are not directly impacted due to the temperature fluctuations.

Soil Requirements

Most varieties of the Japanese Iris, do not like a well-draining, porous, or sandy soil. They like to be grown in soil that can trap water and create a damp and marshy environment. Such a soil must be acidic as well, the pH of the soil must be below 6. If your soil is not acidic, you can add sphagnum peat.

They grow very well in clay and chalk and loam type of soils. The soil must be prepared in a way that it allows the quick spread of the roots of Japanese Iris. The soil for Japanese Iris must be rich in organic matter, this will boost the growth of the plant.

You can also add compost and manure to make the soil nutrients rich. Adding a thin layer of mulch will also help you make your soil more damp/marshy. This type of soil is perfect for growing Japanese Iris.

Fertilizer Requirements

Fertilizing your Japanese Iris plants is important, this can help you see more bloom and also helps your plants grow faster. Japanese Iris plants are considered heavy feeders when it comes to fertilizers.

They are mostly grown in nutrient-rich soil, but they consume all these nutrients quickly and require you to add more nutrients in terms of fertilizers. You can feed them fertilizers once every month.

You need to use the specific fertilizers that are made for the Japanese Iris plants, the general-purpose fertilizers are not good for them as they need a slightly acidic type of fertilizer. Use water-soluble acidic fertilizers to boost their growth.

how to use the fertilizers?

There are three different ways to fertilize your Japanese Iris plants, below are the details about them.

● The first method involves adding some water-soluble acidic fertilizers in the soil, before planting the Japanese Iris plants. When you are preparing the potting soil, you can mix the fertilizers as well. This is considered the best approach if your soil is not nutrient-rich.

● The second method involves adding the plant fertilizer in the soil, (spreading it around the soil and then watering). You take the required amount of fertilizers and then spread it around the stem, and then water your plant. This approach is used once the plants have gained some height.

● The third and most popular method of fertilizing your plants involves creating a mixture of water-soluble plant fertilizers and water. This type of mixture is useful as you just need to spray this in the soil near the plant stem, you are not required to spread and water. You can regularly feed this type of mixture to your Japanese Iris plants once every 35 days.

Before fertilizing your plants, you must read the instructions and guidelines that are provided to you with the fertilizers. These guidelines give insight into the quantity and frequency of the use of fertilizers.

Overfeeding of plant fertilizers to your Japanese Iris plants can severely damage the foliage of the plant, and can also cause the roots of the plants to root. This can lead to the death of the plant as well. So, you need to be careful about the frequency of fertilizing and the amount of fertilizer used every time. It must be according to the guidelines provided with the fertilizer.

Repotting Requirements

Iris Ensata or Japanese Iris plants are not reported but they are divided and replanted into two or more places. Most of the Japanese Iris varieties are planted in this way. Before you can replant them, you need to make sure that you are dividing a mature plant, dividing young plants will not provide any benefits.

Choose a mature plant (that is 25+ inches and is 2 years old), uproot, divide and then replant these divisions into the new pots. Before replanting them, make sure that you have kept the soil moist for almost two days.

Common Diseases and Pests Control

Below are the details about some common diseases and pests, and how to control them on Japanese Iris plants:

Bacterial Leaf Blight: The Bacterial Leaf Blight is commonly seen in most varieties of Japanese Iris, while some varieties are also immune to it as well. This is a disease in which the leaves of Japanese Iris plants start decaying, the blights appear due to bacterial infection. This can lead to the death of your plant, so you must identify and manage it before it can spread. The best thing that you can is to remove all the infected leaves immediately, avoid watering over the foliage, and spray a chemical. If this is not controlled in an early stage, it can kill the whole colony of the plants.

Botrytis Rhizome rot: This is a type of root rot; it is common in rhizome plants (Japanese Iris is a rhizome plant). It is caused by a pathogen named Botrytis Convoluta. This mostly occurs when you plant the infected bulbs. This is characterized by the number of leaves and the color of leaves. You will see that only a small number of leaves emerged and all of these will quickly turn yellow. The best you can is to prevent this by checking the bulbs and only planting those that are not infected.

Crown Rot: Crown Rot is caused by Corticium Rolfsii and is characterized by the slow death of leaves. Fungal threads appear on the leaves and these leaves slowly die. The fungal threads are mostly seen on the base of the leaves. You can prevent this by discarding the infected bulbs. You can also use a fungicide chemical spray against them.

Soft Rot: Soft rot is a common disease among the Japanese Iris plants that is caused by Erwinia carotovora Pv. Carotovora. These symptoms include the sudden collapse of all the leaves and slow death. The plants that are infected by the soft rot also produce a rotting smell. The best you can do against them is to destroy all the infected parts of the plants, including the bulbs. You can also use chemical spray to overcome the attack.

Apart from these pathogen attacks, the Japanese Iris plants are also impacted by some common problems including the low sunlight exposure, less watering, overwatering, and overfeeding of fertilizers. These problems can also lead to slow growth or death of the plants as well. It is advised to keep monitoring the plant’s health, especially the leaves. The leaves show the early signs of any type of pathogen attack or environmental problem.


The Japanese Iris plants are mostly propagated with the help of bulbs, or divisions (underground rhizome stems). You need to take the divisions from a mature plant or divided bulbs from a mature plant. You need proper marshy soil that is acidic and then you can plant them in such a soil. After planting them, irrigate them and let them be under the full sun.

Growing from seeds:

You can also grow the Japanese Iris from the seeds as well, all you need to do is to collect the seeds after the flower turns into the seed pods. Let these seeds pods dry out in the sun, wait for the winter to pass, and then plant these seeds in the ground.

After planting these seeds, keep watering them and make sure the soil remains damp around them. You can also cover the pot with a polythene sheet to create a greenhouse environment. Once the seeds start sprouting, you can take care of them like a normal plant.

Frequently Asked Questions

Question: When to cut back Japanese Iris?

Answer: During the flowering season, you can cut off the faded Japanese Iris plant flowers, this is mostly done to maintain a beautiful look of the plant without flowers. Fading Japanese Iris plant flowers can destroy the overall beauty of the plant, so you can cut them off.

Question: Japanese Iris vs Siberian Iris?

Answer: The basic difference can be characterized by their name, one if from Japan while the other is from Siberia. Both of these are rhizomes but have different looks. Siberian Iris has small flowers, and do not have a beard while the Japanese Iris plants have bigger flowers and a beard.

Question: Are Yellow Japanese Iris real?

Answer: Yes, Yellow Japanese Iris plants are real, they are a variety of Japanese Iris plants. They produce yellow bloom during the spring that lasts till the midsummer. They have similar growing and care requirements as most of the other Japanese Iris varieties.

Question: How long do Japanese Iris bloom?

Answer: The Bloom of Japanese Iris lasts for almost two weeks. The early blooming varieties produce flowers during late spring, while the late-blooming varieties produce flowers during the midsummer.