Divide and Conquer: How to Successfully Divide Bearded Irises

Bearded irises are a lovely addition to any garden or landscape. With their vibrant colors and unique shape, it's no wonder many gardening enthusiasts seek these plants out. However, as with any perennial plant, maintenance is key in ensuring their longevity and beauty. One important aspect of bearded iris care is dividing them. In this article, we'll explore what bearded irises are, why you should divide them, and when the best time to do so is.

What are bearded irises?

Bearded irises, also known as Iris germanica, are a type of herbaceous perennial plant that grow from rhizomes. They are known for their distinctive flower structure, with three upright petals, three drooping sepals, and a fuzzy "beard" on the falls (lower petals). Bearded irises come in a variety of colors, including shades of purple, blue, pink, white, and yellow.

Why should you divide them?

There are several reasons why it's important to divide your bearded irises. First, over time, the rhizomes can become crowded and compete for nutrients and space, leading to decreased vigor and blooming. Dividing the plants and replanting them allows each individual rhizome to have more space and resources, which can result in bigger and better blooms. Second, dividing irises is a great way to propagate and share your plants with others. Lastly, dividing your irises can help control diseases and pests, as removing old or diseased sections can reduce the risk of problems spreading.

When is the best time to divide bearded irises?

The best time to divide bearded irises is in late summer/early fall, after they have finished blooming. This is when the plant is entering its dormant phase, and new roots and growth can begin to establish before winter. Dividing them earlier in the season can interrupt their blooming period and lead to decreased blooms the following year. It's important to make sure each section of rhizome has healthy roots and foliage, and to clean and disinfect your gardening tools between each cut to prevent the spread of diseases.

Step-by-Step Guide to Dividing Bearded Irises

1. Dig up the bearded iris plant: Use a spade or fork to gently dig around the plant, taking care not to damage the rhizomes.

2. Shake off excess soil: Once the plant is out of the ground, gently shake off any excess soil from the roots and rhizomes.

3. Separate the rhizomes: Use clean, sharp gardening shears to cut away the old/decayed parts of the rhizomes. Divide the remaining healthy rhizomes into sections, making sure each section has at least one fan of leaves and some healthy roots attached.

4. Prepare the new planting location: Choose a site with well-draining soil, full sun to partial shade, and plenty of space for the rhizomes to spread out.

5. Plant the divided rhizomes: Dig a hole large enough to accommodate the rhizome section, and place it in the hole so that the top of the rhizome is level with the soil surface. Space each section at least 12 inches apart.

6. Water and mulch: Water the newly planted rhizomes thoroughly, making sure the soil is moist but not waterlogged. Cover the soil with a layer of mulch to help retain moisture and control weeds.

7. Care for the rejuvenated plants: Continue to water regularly and fertilize according to the plant's needs. Monitor for pests and diseases, and remove any dead or diseased foliage promptly.

Tips for Success:

• Don't divide your irises until they are at least three years old, as younger plants may not yet have enough energy reserves to recover from division.
• If you're dividing a large number of irises, label each section with a marker or tag to keep track of the different varieties.
• Don't bury the rhizomes too deep when planting, as this can lead to rot and other problems.
• Always use sharp, clean gardening tools when working with your plants to prevent the spread of disease.

Dividing your bearded irises is an important step in maintaining their health and helping them thrive. By following these simple steps, you can easily divide and replant your irises for a rejuvenated garden. Remember to choose a site with good soil drainage, space out your sections evenly, and monitor your plants for pests and diseases. With proper care and attention, your bearded irises should bloom beautifully for years to come. Happy gardening!

FAQ

Here are the answers to some frequently asked questions about bearded irises.

How often should bearded irises be divided?

Bearded irises should be divided every three to five years. If left undivided for too long, they may become overcrowded and stop blooming.

Can I divide bearded irises in the summer?

It is not recommended to divide bearded irises in the summer, as this can stress the plants and make them more susceptible to disease. The best time to divide bearded irises is in late summer or early fall, after blooming is finished.

Do I need to sterilize my tools before dividing bearded irises?

Yes, it is important to sterilize your tools before dividing bearded irises to prevent the spread of disease. You can use rubbing alcohol or a 10% bleach solution to disinfect your tools.

What is the best soil for bearded irises?

Bearded irises prefer well-draining soil that is slightly acidic with a pH between 6.0 and 7.0. You can amend heavy clay soils with organic matter to improve drainage.

How long does it take for a divided bearded iris to bloom again?

A divided bearded iris can take up to two years to fully establish new roots and produce blooms again. However, some varieties may bloom sooner than others.

Do all varieties of bearded iris need to be divided?

No, not all varieties of bearded iris need to be divided on a regular basis. Some varieties may not need to be divided ever, while others may require division more frequently depending on their growth habits and conditions in your garden.