Iris Care: Information On Iris Plant Care

By: Becca Badgett, Co-author of How to Grow an EMERGENCY Garden

Several varieties of iris plants (Iris spp.) exist, providing intricate and exquisite blooms in sunny areas of the landscape. Iris flowers begin blooming in late winter to early spring. A range of varieties provide extended color in the flower bed.

Iris care is minimal once the growing iris is established. Iris plant care consists mainly of dividing the iris plants to assure continued blooms. Iris plants are abundant multipliers but once the rhizomes of iris plants become crowded, the iris flowers may be limited and the rhizomes need to be separated.

About Iris Flowers

The most commonly planted iris in the United States is the bearded iris. Height of the bearded iris plant ranges from 3 inches for the shortest of dwarf iris flowers to 4 feet for the tallest of the tall bearded iris. Those iris plants in the intermediate group reach 1 to 2 feet in height.

Iris flowers bloom in shades of purple, blue, white and yellow and include many hybridized versions that are multi-colored. Louisiana ‘Black Gamecock’ iris of the Louisiana series is such a deep purple it almost appears black. Siberian iris flowers are more dainty, but also available in a plethora of colors. ‘Butter and Sugar’ cultivar is a delicate yellow and white.

The Spuria iris, planted along with the Siberian iris, offers blooms later in the spring once the bearded iris bloom is finished. Many of the flowers are ruffled and include a draping set of three outer sepals called falls.

Tips for Growing Iris

Plant rhizomes of the iris in a sunny location with well draining, rich soil for optimum flowering. Leave room for growth between the rhizomes and do not bury the entire rhizome. Make sure roots are covered, but allow the iris rhizome to remain partially above ground to avoid root rot.

Once blooms fade, leave the foliage to yellow before removing from the flower bed. Plant so later blooming specimens cover the remaining foliage. As with many spring blooms, the foliage is sending nutrients to the rhizome for next year’s flowers. This is one of the difficult parts of iris care, as many gardeners wish to immediately remove foliage once flowering is done.

Other iris plant care includes watering during dry spells, fertilization before flowers appear and deadheading of the spent blooms. However, most clumps of iris provide flowers with no maintenance. Iris is drought tolerant and may be part of a xeric garden; keep in mind, even drought tolerant plants benefit from an occasional watering.

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How to Grow Dutch Irises

The Spruce / Evgeniya Vlasova

Dutch iris (Iris × hollandica) is a hybrid type of bulbous iris. The common name does not refer to its native origin but rather to the fact that it was the Dutch who hybridized it. Iris xiphium, the parent most associated with Dutch iris, is actually native to Spain and Portugal.

The flowers, which are typically three to four inches wide, are usually multi-colored. Blue, bluish-purple, white, and yellow are the most common predominant colors.

Dutch iris is not grown for fragrance, but it does make for a good cut flower. In fact, you may know it from floral arrangements that you have given or received, especially around Easter time.

Although this is a short-lived plant, it is easy to grow and, with the right sunny and well-drained conditions, it can naturalize in your garden, giving you a new set of flowers every year.

Dutch iris plants look their best when they are massed together in the landscape. For example, they work well in flower borders in sunny areas. Install them along a walkway or in a foundation planting, or they may also be grown in containers.

Botanical Name Iris × hollandica
Common Name Dutch iris, Dutch hybrid group, fleur de lis
Plant Type Bulb
Mature Size 1.5 to 2.0 feet tall, with a spread of .25 to .50 feet
Sun Exposure Full sun
Soil Type Well-drained, with average moisture and fertility
Soil pH Mildly acidic, neutral, mildly alkaline
Bloom Time May to June
Flower Color Most commonly blue, bluish-purple, white, yellow
Hardiness Zones 6 to 9, USA
Native Area Hybrid (parent, Iris xiphium, native to Europe)
Toxicity Non-toxic, but avoid ingesting

When is the Best Time to Plant Irises

Iris are usually shipped from growers in August and September for a reason.

This gives most gardeners the chance to get the in the ground in time for the rhizomes to settle in and start rooting.

This is also the time that you would dig up and divide the Iris currently growing in your garden.

After you have either dug up and divided your rhizomes or you have just received some from an iris farm you need to plant them correctly to get the most from them.

What Are Some Tips on Planting and Taking Care of an Iris Plant?

Iris plants are one of the most preferred plants for flower beds. There are different varieties of Irises that provide stunningly coloured flowers in your garden. Important among them are Bearded irises, English irises, and Siberian iris. Gardeners prefer this plant as they need to provide it with little care once the plants are established. These plants propagate by forming rhizomes. Moreover, the plant provides blooms continuously once they start flowering. Here are some tips on planting and taking care of an iris plant.

Tips for Planting Irises

  1. Late summer or early autumn is the right season to plant iris rhizomes. Plant the rhizomes or bulbs when the conditions are ideal for growth.
  2. Iris needs a sunny location for proper growth and flowering. So, plant them in areas with direct sunlight.
  3. Plant Irises in rich and well-draining soil under the rhizome to prevent root rot and to improve their flowering.
  4. Select rhizomes that are at least thick as your thumb and have 1 to 2 leaf fans and healthy roots for planting.
  5. Clip off the leaves to a length of 4 to 6 inches before planting to prevent wind rock and reduce the stress for the plant to maintain the leaves while they concentrate on a new root growth.
  6. Leave enough space between rhizomes while planting. Keeping a distance of 14 to 18 inches is ideal. Dwarf varieties of irises require less space between them than the tall bearded varieties.
  7. In areas receiving high rainfall, plant them in raised beds for better drainage.
  8. It doesn’t matter which way you plant your iris rhizomes whether they are facing north, south, east or west. Lets face it, after 12 to 18 months your iris will clump up and you would never know from day one which way your rhizomes originally faced. Its more important to make sure that the iris leaves are straight when the iris division is planted.
  9. Plant the rhizomes in such a way that the roots and the top part of the rhizome are lightly covered in soil to prevent the rhizome from scalding by the hot sun.
  10. Even though they are drought-tolerant, keep irises watered during the growing season and they may require occasional watering once a week during dry spells.

Tips Caring for your Irises

  1. Hybrid varieties of irises need more fertilisers than the regular varieties.
  2. Fertilise the plants before the blooms appear and after dividing with slow release fertiliser blood and bone or superphosphate and potash for optimal flower production.
  3. Overcrowding and clumping will reduce flower production and hence plant clumps need division.
  4. Lift iris clumps using a garden fork during late summer and separate and select the younger vigorous plants for replanting.
  5. The use of lime is not necessary unless your soil is on a pH scale below 5.5 very acid.
  6. Keep iris flower beds free from weeds to avoid competition.
  7. Once the blooms of the plant fade, remove the flower head. Make sure that the stem and foliage are intact as possible.
  8. Removing flower heads prevents seed pod formation and prevents the growth of seedlings around the plant.
  9. Allow the stem and foliage to turn yellow before removing it. The plant requires the foliage to send nutrients for storage to the rhizome for next season’s flowering.
  10. Division of the clumps is necessary every 3 to 4 years or when the plants are overcrowded.
  11. The plant may need mulching during winter.
  12. Slugs and snails are the enemies of irises. So, pick them with your hand or use slug baits.

Different varieties may require different types of soil and fertilisers. Take care of the Irises depending on their type.

With a few tips and tricks, you can enjoy iris for years. Here are a few simple tips:

  • The foliage on iris grown from bulbs should be allowed to fade naturally and should not be cut. The foliage is key to making food for next year’s bulb.
  • After blooming, German Iris prefer drier soil and good air circulation. They thrive in borders and mixed perennial beds. The foliage should not be cut off before midsummer
  • If planting iris near water features, consider Japanese, Siberian or Louisiana iris because they don’t mind moist soil.
  • Iris make spectacular cut flowers, so consider growing enough to enjoy in the garden and cut-flower arrangements.

How to Divide Iris Flowers (Rhizomes)

Do you grow irises around your home or in a garden bed? Do you enjoy their vibrant beauty and how easy they are to care for?

If you’ve grown iris flowers for any length of time, you’ve probably acquainted yourself with the anatomy of this plant.

You know it has beautiful green foliage which produce a range of colorful blooms. You also know the base of the plant, where the foliage starts, is called a rhizome that leads into the plant’s root system.

Why is this important? Because over time, the rhizome will stop producing. If you’d like to learn how you can keep your irises blooming for years to come, you need to know how to properly divide the rhizomes.

Here’s what you must know to divide your iris flowers’ rhizomes to produce even more plants and color around your home or garden:

Why Divide Rhizomes of the Iris Plant?

As your iris plant becomes established, the rhizome will grow along with it. During this growth process, the “mother” rhizome reproduces baby rhizomes.

This will lead to more foliage and blooms producing in the grow space. Eventually, the mother rhizome will run its course.

Overtime, the original rhizome will stop producing new rhizomes, blooms, and foliage and eventually die.

When you see this beginning to happen, it lets you know it’s time to divide the mother rhizome. This will allow the newer rhizomes to grow, bloom, and take on the “mother” role.

The Process of Dividing the Iris Plant Rhizomes

Now that you understand why dividing rhizomes is important, you must understand the proper technique to performing this task. You don’t want to begin hacking into your plants and ruining your flowers.

By following these steps, you should have an easier time dividing the rhizomes and have a greater chance at reducing harm to your plants.

1. Out with the Old Iris Plant Rhizome

When you see the mother rhizome starting to die back and failing to produce new foliage or blooms, it’s time to begin the division process.

Start by digging up the old rhizome. Use a shovel, spade, or pitchfork to dig beneath the earth and pull out the mass of rhizomes.

The idea is to use the tool that makes the cleanest cut through the rhizomes to pull them out of the earth with little to no damage.

Once you’ve gotten beneath the mass, made your cut, and have heaved it up from the earth, you should be staring at a large clump of rhizomes. If you’ve made it this far, you’re starting off on a positive foot in this process.

2. Separate the Iris Plant Rhizomes

The next step in the division process is to separate the mass of rhizomes into individual rhizomes. Depending upon how firmly clumped they are, will determine how you go about separating the mass.

If the rhizomes are loosely clumped together, you should be able to use your hands to carefully pull them apart.

However, if the mass is woven tightly, you may need to use a sharp knife to separate it. It’s vital to sanitize your knife in a bleach solution between cuts.

If you slice into a rhizome that is infected, and don’t sanitize your knife between cuts, you can spread the disease to other rhizomes. The sanitizing solution should be one-part bleach to ten parts water.

Once your rhizomes are separated, begin looking at them to see which are healthy and which are not. A healthy rhizome will be approximately two inches in diameter, have a strong root system, and two or more leaves on it.

If the rhizomes don’t appear young and healthy, get rid of them because they most likely won’t form healthy plants.

This is also the time to discard the mother rhizome. She’s served her purpose and shouldn’t be intertwined with the new rhizomes for transplanting.

After reviewing your newly separated rhizomes, you’re ready to move forward in the process.

3. Remove the Dirt of the Iris Plant Rhizome and Inspect

You’ve separated your rhizomes and separated the weak from the strong. It’s now time to pull the dirt back and look even closer to make sure you’re only saving the healthiest of rhizomes from each clump you’ve removed from your garden space.

Wipe the dirt off the rhizomes you saved and begin inspecting them for pests. Iris borers can cause serious issues because they feed off the rhizome.

If you see any iris borers, kill them between your thumb and index finger. Look closely at the rhizome you found the pest dwelling on. If the rhizome looks healthy, keep it. If the borer has caused damage, it’s better to toss that rhizome.

Once you’ve inspected each rhizome, it’s time to disinfect them. Gently rinse each rhizome with a bleach disinfectant.

Again, make sure it’s one-part bleach to ten parts water. This can help ward off any diseases that may try to ravage your newly transplanted rhizomes.

After disinfecting, check your rhizomes one more time. If any have a bad odor about them or feel squishy, they don’t need to make the cut for transplanting.

4. Trim the Foliage of the New Iris Plant Rhizomes

Your rhizomes are clean, disinfected, and thoroughly inspected. What could possibly be left? All they need now is a trim.

This isn’t for aesthetics. Instead, by trimming the foliage back to only three to six inches in length, it allows the plant to put all its energy into establishing a solid root system.

If you leave the foliage longer, the plant will send nutrients to it because it thinks it’s still trying to maintain quality health in this area.

By cutting the foliage back, it sends a message to the plant to divert the energy to the roots because that’s where it’s really needed.

After you’ve trimmed each rhizome’s foliage back to only a few inches, they’re ready for transplant.

5. Transplant the New Iris Plant Rhizomes

Transplanting an iris rhizome isn’t a complicated process. You should find a location that provides well-draining soil and ample sunlight.

The rhizome needs approximately six hours of full sun per day. These two grow requirements are vital to ensure the rhizome remains dry to avoid rot.

Also, more sunlight equates to more blooms. If you want the most color you can get from your irises, keep them healthy and provide the light they desire.

When it’s time to dig the holes for transplant, ensure they’re approximately four inches deep and at least two feet apart.

You might be able to get away with them being a little closer if you choose a miniature variety of the iris plant.

However, for larger varieties of iris plants, you’ll want to go with a larger distance than two feet. Once the holes are dug, place the rhizome into the space.

Ensure the rhizome is erect while the roots are spread out. The rhizome should be sitting at soil level where you can see at least one to two inches of it.

This will ensure it receives proper sunlight while also avoiding putting too much pressure on the roots. If the rhizome isn’t sitting high enough, the roots can become compressed in the space.

When all the rhizomes have been planted, water them well. Irises only need water during drought and right after transplant. By watering them during this time, you’re doing your part to give these plants a proper start.

Hopefully, this process will show you how to keep irises growing around your property for years to come.

Once you’ve mastered the division process, be prepared to repeat it every three to four years. This will keep your home booming with color all summer long.

Watch the video: Iris Care: Pests and Disease

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