| Dividing Irises |
From "Ask DIY"
episode ADI-613 |
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Q: What is the proper way to divide an iris? A: (Walter Reeves, DIY horticulturist and gardening expert) Dividing irises is easy, and is something that anyone can accomplish with iris plants that have been growing for two years or more. Here are the basics of what you should know:
- Like many plants, most irises (figure A) grow and spread by putting out horizontal stems known as rhizomes that grow along the ground or just beneath it.
- Carefully dig up a clump of irises, and inspect the root structure. Look for a good place to gently separate sections of the roots by hand (figure B).
- With the plants pulled apart, you may be able to see portions of the separated rhizomes (figure C) where the offshoots connected to the mother-plant. The rhizomes may be only an inch or so long, or they may be several inches -- depending on how crowded the growing conditions of the plants have been. Plant growth and foliage will be healthier if the plants are separated periodically so the roots and rhizomes don't get packed too tightly together.
- Once you've divided your iris into two (or several) pieces, trim back the foliage on each clump with scissors (figure D), creating a fan-shape with leaves about 8 to 10 inches in length. This reduction in foliage will help the new plantings get off to a good start, since the roots won't need to supply as much leaf portion with water and nutrients. Once the roots have recovered from the shock of being moved, the foliage should grow back even healthier than before.
- Most common irises -- such as bearded irises -- need to be divided every 4 to 5 years for the healthiest growth. Siberian iris forms a more dense root-ball (figure E), and needs to be divided about every 2 years. Use a shovel or reciprocating saw to separate the denser roots of Siberian irises.
- Replant divided irises (figure F) in good soil that's rich in organic nutrients and has good drainage.
- Because the rhizomes grow best at the soil surface, replant the divided irises at a depth so that the rhizomes are close to the surface (figure G), and not buried too deeply.
- Iris Tip: Irises are susceptible to infestation by an insect known as the iris borer. Insecticides are not very effective on this species of insect. If you see a spot where one of these parasites has bored into the leaf, simply pinch the spot firmly between your fingers (figure H) to kill the borer.
RESOURCES :
Daylilies: The Perfect Perennial
Model: 0882666517
Author: Lewis Hill
Storey Books
April 1991
Easy Care Shade Flowers
Model: 0671755676
Author: Patricia A. Taylor
February 1993
Taylor's Master Guide to Landscaping
Model: 0618055908
Author: Rita Buchanan
Houghton Mifflin Co.
Boston, MA 02116
Phone: 617-351-5000
Email: tradecustomerservice@hmco.com
Landscaping: Planning, Planting, Building (Better Homes and Gardens Step-by-Step Series)
Model: 0696025582
Meredith Books Corp.
Website: www.meredith.com
Landscaping: Principles and Practices
Model: 082736735X
Author: Jack E. Ingels
Delmar Learning
Taylor's 50 Best Perennials for Sun: Easy Plants for More Beautiful Gardens
Model: 0395873304
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