How to Divide Irises: StepbyStep Guide for Healthy Blooms

How to Divide Irises?

To divide irises, wait until after they have finished flowering and become dormant in late summer.

Snip the leaf blades to reduce stress before carefully removing the clump with a spade or garden fork.

Gently pull apart the rhizomes by hand, or use a sharp knife that has been dipped in a bleach and water solution.

Discard any large, old rhizomes without leaf fans and check each rhizome for iris borer or signs of rot.

Plant the rhizomes singly or in groups of three, spacing them 12 inches apart for the best display.

Water thoroughly when newly planted and avoid mulching to prevent rot.

Bearded irises thrive in well-drained soils with a pH of 6.8.

Newly planted irises should have well-established roots before the first frost.

Trim leaves in the fall and remove seedpods to conserve energy.

Keep iris beds clear of weeds and fallen leaves.

Dividing rhizomes is a good way to multiply irises for sharing with others.

Key Points:

  • Wait until after flowering and dormancy in late summer to divide irises
  • Snip leaf blades before carefully removing the clump with a spade or garden fork
  • Gently pull apart the rhizomes by hand or use a sharp knife dipped in a bleach and water solution
  • Discard any large, old rhizomes without leaf fans and check for iris borer or signs of rot
  • Plant rhizomes singly or in groups of three, spacing them 12 inches apart
  • Water thoroughly when newly planted and avoid mulching to prevent rot


Did You Know?

1. Did you know that the exact process of dividing irises is called “rhizome division”? This technique involves separating the rhizomes, which are the thick, fleshy underground stems of the plant.

2. While most irises are divided every three to five years, there is one particular species called the Japanese iris that should only be divided every eight to ten years. This is because they have a slower growth pattern compared to other iris varieties.

3. Irises have the ability to change color based on the acidity of the soil they are planted in. This phenomenon is called “color breaking,” where blue or purple irises turn pink or red when exposed to more alkaline soil conditions.

4. Some people believe that ancient Egyptians used iris rhizomes for medicinal purposes. Historical records suggest that irises were utilized in treating ailments such as skin irritations, toothaches, and even digestive problems.

5. In the language of flowers, the iris holds symbolic meanings. In Greek mythology, it is associated with the goddess Iris, who was a messenger between gods and humans. Consequently, irises commonly symbolize communication, wisdom, faith, and hope.

Introduction To Irises: A Look At The Oldest Garden Flower

The iris, named after the Greek goddess of the rainbow, is an exquisite flower that has been cultivated for centuries. With its vibrant colors and delicate petals, it is no wonder that the iris is one of the oldest garden flowers in existence. The iris is not only known for its beauty but also for its hardiness and reliability, making it a popular choice for gardeners worldwide.

One particular type of iris that stands out is the bearded iris. It is not only easy to grow, but it also attracts butterflies and hummingbirds, adding a touch of enchantment to any garden. There are approximately 200 to 300 species of irises, with the tall bearded iris being the most familiar variety. These bearded irises are characterized by their tall, slender stems and distinctive fuzzy beard-like appendages on the falls.

  • Iris is an exquisite flower cultivated for centuries, known for its beauty and hardiness.
  • Bearded Iris is a popular variety known for its easy cultivation and ability to attract butterflies and hummingbirds.
  • There are approximately 200 to 300 species of irises.
  • Tall bearded iris is the most familiar variety, characterized by tall stems and fuzzy beard-like appendages on the falls.

“The iris is an exquisite flower that has been cultivated for centuries, known for its beauty and hardiness.”

Dividing Bearded Irises: Tips For Success

To ensure healthy and abundant blooms, it is necessary to divide bearded irises every three to five years. This process is vital as it prevents the clumps from becoming overcrowded, which can lead to reduced bloom production.

Dividing should be done after the flowering season, during late summer when the irises become dormant.

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Before dividing, it is recommended to snip the leaf blades to about one third of their original height. This helps reduce stress on the plant and allows for easier handling during the division process. Carefully remove the clump from the ground using a spade or garden fork, being cautious not to damage the rhizomes. Once removed, gently pull apart the rhizomes by hand, taking care to separate them without causing harm.

  • Divide bearded irises every three to five years
  • Divide after the flowering season, during late summer
  • Snip the leaf blades to about one third of their original height
  • Carefully remove the clump from the ground
  • Gently pull apart the rhizomes by hand without causing harm

Understanding The Different Types Of Irises

Irises are flowering plants that can be classified into two major groups: rhizomatous and bulbous.

Rhizomatous irises, such as the bearded iris, have horizontal underground stems called rhizomes. These rhizomes not only store energy for the plant but also help it spread.

Bulbous irises, on the other hand, grow from bulbs. These bulbs are modified underground stems that store nutrients.

The bearded iris is the most well-known and widely grown type of iris. It can be further divided into different classes based on its height, flower form, and color patterns.

The tall bearded iris is the most popular variety, standing over 27 inches tall and showcasing large, showy blooms. Other classifications include intermediate bearded iris, miniature tall bearded iris, and border bearded iris, each with its own unique characteristics and size.

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When And How To Divide Bearded Irises

Dividing bearded irises should be undertaken every three to five years to ensure continued healthy growth and blooming. The best time to divide irises is after they have finished flowering, usually during late summer or early autumn. This period corresponds to the time when the irises become dormant.

To divide the irises, begin by snipping the leaf blades to one third of their height. This reduces stress on the plants and facilitates the division process. Gently remove the clump from the ground, taking care not to damage the rhizomes. If necessary, a sharp knife can be used to separate the rhizomes, ensuring that each division has healthy roots and one or two leaf fans.

It is important to inspect each rhizome for signs of iris borer, a common pest that can damage the plant. Any affected rhizomes should be destroyed to prevent the spread of the pest. Additionally, soft, smelly, or rotting rhizomes should be discarded and not composted to avoid contamination.

  • Snip the leaf blades to one third of their height
  • Gently remove the clump from the ground, being careful not to damage the rhizomes
  • Separate the rhizomes using a sharp knife, ensuring healthy roots and one or two leaf fans
  • Inspect each rhizome for signs of iris borer and destroy any affected ones
  • Discard soft, smelly, or rotting rhizomes to avoid contamination.

Note: Remember to take precautionary measures for healthy growth and blooming.

Ensuring Healthy Rhizomes: Selection And Care During Division

When dividing bearded irises, it is crucial to select healthy rhizomes for replanting. A good rhizome should be about as thick as your thumb, have healthy roots, and possess one or two leaf fans. Large, old rhizomes with no leaf fans should be discarded as they are less likely to produce vigorous growth and blooms.

To prevent the spread of diseases and pests, it is advisable to dip the knife used for dividing in a bleach and water solution after each cut. This sterilizes the knife and helps minimize the risk of contamination.

Planting And Maintaining Irises For The Best Results

When planting bearded irises, select a well-drained area in your garden. These irises thrive in soils that do not become waterlogged, as excessive moisture can cause the rhizomes to rot. The ideal pH for irises is 6.8, but they are tolerant of less-than-perfect soils. It is recommended to test the soil before making any corrections.

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When planting the rhizomes, dig a shallow hole and center the rhizome on a soil mound, with the top surface just visible. Plant rhizomes singly or in groups of three, ensuring that the fan of leaves faces the same direction. Space the plants 12 inches apart to allow for optimal growth and display.

After planting, water the newly planted rhizomes thoroughly to settle the soil and provide hydration. However, it is important to avoid mulching around the rhizomes, as this can lead to rotting. Mulching is best kept away from the base of the plants.

Throughout the growing season, ensure that weed and fallen leaves are kept clear from the iris beds. This allows the rhizomes to bask in the sun and receive the necessary warmth and light for healthy growth. Additionally, trim the leaves only in the fall, removing any brown tips and cutting the flowering stalk to the ground at a slant. This helps discourage rot and prepares the plants for winter dormancy.

Frequently Asked Questions

What is the best time to divide irises?

The optimal time to divide irises is during late July through mid-August. This period is ideal for planting, moving, or dividing these popular and low-maintenance perennials. Despite their ability to thrive with minimal care and provide years of enjoyment, regularly dividing irises is crucial for maintaining their overall health.

How do you propagate irises?

One way to propagate irises is through asexual propagation using their rhizomes. By cutting off a portion of a rhizome and replanting it, one can successfully grow a new plant identical to its parent. This method allows for easy multiplication of irises, as they naturally spread using their rhizomes as well.

How do iris multiply?

Iris plants have a fascinating way of multiplying through their underground stems known as rhizomes. Over time, these rhizomes become overcrowded, leading to a decrease in flowering. However, you can revitalize the older planting and even create new ones by lifting and dividing the larger clumps. This process not only helps rejuvenate the existing iris bed but also allows you to expand your garden or share the extra plants with friends. By understanding and utilizing this natural multiplication method, you can maintain a flourishing iris garden for years to come.

Can you divide iris anytime?

Yes, iris can be divided, but it is crucial to select the appropriate time for this task. It is recommended to divide iris after flowering, during the late summer when they enter their dormant phase. Dividing them at this time helps minimize the risk of bacterial soft rot. On the contrary, dividing iris during the winter months should be avoided as they rely on stored energy in their rhizomes to survive.

References: 1, 2, 3, 4

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