LATE SUMMER IS THE TIME TO DIVIDE YOUR BEARDED IRIS
Did you know that you should divide your bearded iris every 2 to 3 years to maintain plant health and encourage new blooms? If you've been noticing that your irises are blooming less and less every year, it's time to divide. Seems like a daunting task? Yes, bearded iris are a bit high maintenance, but it's not that difficult. All you need is a little time and some patience. Here's how it's done, step-by-step:
1. TOOLS/EQUIPMENT REQUIRED:
- A gardening or pitch fork.
- Sharp pruners and/or sharp horticulture or pruning knife.
- 10% bleach solution (nine parts water to one part bleach) for disinfecting cutting tools.
2. CAREFULLY LIFT OUT IRIS RHIZOMES using the gardening/pitch fork. Try to be careful and not puncture the rhizomes with the fork. Set the rhizomes aside until you have finished lifting out the entire clump. If after lifting out the rhizomes you notice that they are covered in dirt and it's difficult to see the rhizome itself you will need to use a hose and wash off the dirt. This is important as you will need to examine the rhizomes.
3. CHECK EACH RHIZOME FOR HOLES OR SIGNS OF DECAY. Cut these parts off using pruners or a knife, making sure to dip your cutting tool into the bleach solution after each cut. This will disinfect the tool and prevent the spread of disease. Keep an eye out for hollow or mushy rhizomes, as this is the work of the iris borer (Macronoctua onusta). It is a moth larvae that likes to dine on iris rhizomes. While its eating habits are destructive enough, it also infects rhizomes with bacterial soft rot which can be spread through improper cultivation practices (ie: not disinfecting cutting tools).
Iris borer making a snack out of an iris rhizome.
Bacterial soft rot.
Photo Credit: Michelle Grabowski http://www.extension.umn.edu/garden/diagnose/plant/annualperennial/iris/leavesspots.html
Adult iris borer (Macronoctua onusta).
4. DIVIDE THE RHIZOMES. Each iris rhizome should be divided into pieces that are 3-4 inches long and have at least 1 fan of leaves on the rhizome. Do not remove the roots from the rhizomes. As you get closer to the center of the clump, you may find large sections of rhizomes that have no leaf fans. These can be diiscarded. While you are doing this, continue to check all of the divided iris rhizomes for iris borers and disease. The iris rhizomes should be firm and not soft. If the rhizome feels soft, throw it away.
5. CUT THE LEAVES back to about 6". Now you're ready to plant!
6. PLANTING
Choose a sunny location. Bearded iris requires full sun (6 - 8 hours accumulative sunlight). They also require well-drained soil and do not like to be mulched once they have been planted. Plant rhizomes 16 - 18 inches apart.
Plant your rhizomes at or just barely below the surface of the ground. Irises should be planted so the tops of the rhizomes are visible and the roots are spread out facing downwards in the soil. Pat the soil firmly to anchor the rhizomes until new roots begin to grow, and water well. It is a common mistake to plant irises too deeply.
1) Build up a small mound of soil in the center of the planting hole.
2) Centre the rhizome on the soil mound and spread out the roots on either side.
3) Firm the soil around the roots. Newly planted rhizomes should be watered thoroughly.
 |
| Photo Credit: http://www.irises.org/About_Irises/Cultural%20Information/Grow_Bearded.html |
It is recommended that you do not plant your irises in a straight line. Instead, try a triangular layout. This will result in a fuller-looking planting:
 |
| Photo Credit: http://www.irises.org/About_Irises/Cultural%20Information/Grow_Bearded.html |
By the way, this planting technique also works when you are mass planting any sort of plant material.
Irises are perennials and require time to grow. New growth may be noticeable within 2-3 weeks and begins with a new center leaf in the fan. Depending upon the maturity of the rhizome and the geographical location, there may or may not be blooms the first Spring.
No comments:
Post a Comment