Irises come in several varieties and bring color and beauty to gardens in the spring. Irises are typically thought of as in-ground plants. If you do not have an outside garden or if you want to adorn your patio with these beautiful irises, can you grow them in containers?
Irises can be grown in containers by choosing the right container for the iris size. Dwarf irises can thrive in containers from 6 to 8-inches in diameter and with a similar depth. Larger iris varieties require a 12-inch diameter container at least 12-inches deep to provide sufficient root space.
Even though irises are not your typical container plant, they can be grown successfully in containers. The secret to irises flourishing in containers is choosing the right container for the right type of iris and taking care with the planting and care of the irises in the limited growing environment.
Can Irises Grow In Containers?
There are several varieties of iris plants, varying in size and height. All irises can be planted in containers and can do well in this growing environment if the plants’ requirements are met.
The variety of iris you choose to plant will determine the type and size of container required to get the best growth and blooms from the plants.
The method for planting the new irises in the container, as well as their care after planting, will play a role in the overall success of the plant and flowering.
What Irises Are Best For Container Growing?
Irises come in various sizes, and while all irises can be grown in containers, the most popular variety for containers are the dwarf iris variety.
Some iris varieties, like the bearded iris, are tall varieties that may be too tall for a container. The height of these irises may elevate the flowers to about eye level, with may not look visually appealing in the container. Tall iris plants may also require staking for additional support when grown in a container.
In contrast, dwarf iris are much shorter and, when planted in containers, raise the flower head to a more visually appealing level and make the beautiful flowers more noticeable. These reasons make the dwarf iris varieties more popular for container growing.
Most tall iris plants are categorized into bearded irises or crested irises. The bearded iris varieties do better in containers than the crested versions. This is primarily due to the bearded iris having a shallower root system better suited for container cultivation.
What Containers Are Best For Growing Irises?
The container size for growing irises will depend on the variety of irises you have chosen. The smaller dwarf varieties will do well in a container from 6-inches to 8-inches in diameter with a minimum depth of 6 to 8-inches.
The smaller plants have smaller rhizomes and do not need as much lateral or vertical depth in the container.
Larger iris varieties, such as the bearded iris, require a wider and deeper container for optimal growth. A container with a width or diameter of 12-inches and a depth of at least 12-inches is recommended for the larger iris varieties.
Terracotta containers make for the best pots for the iris because they assist with drainage and soil temperature moderation in the containers, especially in the winter. Plastic containers can be used as an alternative, but they need to have adequate drainage to prevent the iris roots from becoming waterlogged and rotting.
What Soil Should You Use In Containers For Irises?
Iris plants like well-drained soil that does not allow the growing medium to become too wet. Damp soil is ok, but wet soil will result in the rhizome suffering from rot and will cause the plant to die.
Iris plants prefer soil that is high in organic matter, well-drained, and with a slightly acidic pH of 6.5 to 6.8. A premium potting mix with added perlite or vermiculite to improve drainage is the best option for these plants. The soil pH can be adjusted by adding a little peat moss to the mixture.
How To Plant Irises In Containers
Summer is the best time to plant irises in containers as this will allow the plant to become established before it faces its first winter.
Iris plants do not do well in the cold in their first year of planting and should be brought indoors for the first winter season. After this time, they can be left outdoors unless you have freezing winters.
Iris rhizomes must not be planted too deep. They prefer being close to the soil surface, so you should plant the rhizome with the very top protruding from the soil.
Irises that grow from bulbs prefer to be planted deeper in the growing medium. The rule of thumb is to plant these bulbs at a depth that is 3 times the size of the bulb.
If you are planting the irises from seed, plant the seeds ½-inch to ¾-inch deep and lightly water the seeds to bed them in.
How To Care For Irises In Containers
Once the irises have sprouted, they will need to be watered regularly to prevent the soil from drying out significantly, but not so much that the soil is wet.
The best way to water irises is to only water if the soil is dry enough rather than watering every day as a routine.
To test if the soil requires watering, push your finger into the top layer of soil to your second knuckle. If the soil feels moist at this depth, watering is not necessary. If the soil at this level, about 1-inch down, feels dry, give the container a watering.
Irises prefer to be in full sun, requiring 6 to 8 hours of sunlight each day. The higher exposure to sunlight encourages the plants to bloom, and you will be rewarded with a better floral display.
In the first year of planting in a container, it will be necessary to protect the plant from cold winter temperatures by bringing it indoors. This action is of particular importance if you experience frost during your winters.
After the first year, the iris should be well enough established in the container to survive the winter outdoors.
After 3 to 5 years in the container, you will need to dig up your iris plants to break up the rhizomes to make space in the container. The rhizomes expand as the plant grows, and if there is not enough space in the container, it will inhibit the growth and flowering of the iris.
After the flowering season, dig up the iris rhizomes and split them into chunks. Keep some to replant the following summer, and you can plant the excess in different containers or offer them to friends and family who may like them for their own container growing.
When the flowers have faded and died, you need to deadhead the iris to keep the plant healthy and looking good. Cut the flower stem off close to the base of the plant, but leave all the remaining leaves intact.
How To Feed Irises In Containers
Irises do not need much feeding and are fairly low maintenance in this regard. If you feed your irises, offering them low-nitrogen food such as bone meal is best.
A high-nitrogen fertilizer will promote lots of leafy growth but will inhibit flowering. The best time to feed your irises is mid to late spring to get the best results.
Conclusion
Irises are popular garden plants that bring color and diversity to any garden. Growing irises in containers allow you to bring this attractive floral display closer to your home.
Irises can be grown successfully and relatively easily in containers if the basic guidelines are followed. Why not try planting your next batch of iris rhizomes in a container to showcase their beautiful blooms around your home?
References
https://www.gardenersworld.com/how-to/grow-plants/how-to-plant-pot-grown-bearded-irises/
https://plantcaretoday.com/potted-iris.html
https://plantcaretoday.com/soil-for-iris.html
https://www.schreinersgardens.com/growing-bearded-iris-in-containers
https://www.gardeningknowhow.com/ornamental/bulbs/iris/potted-iris-care.htm
