Click below to listen to my 2 min. Garden Bite radio show: Dividing iris
If your iris rhizomes are rising out of the ground, it’s time to divide them!
Maybe they’ve been left alone for years and are now fighting for room, maybe this is a “new to you home” and you’ve noticed that those roots look like they’re squeezing each other.
Generally it’s a good idea to divide your iris every 3 to 4 years. In my area the season has been late, so you might need to wait a bit before dividing them. Dividing iris should be done 4 to 6 weeks after blooming, which is generally between July and early August according to the University of Minnesota Extension. More information from the University of Wisconsin Extension.
When it’s time, cut the foliage fan back to about 3 to 6 inches.
Remove yellow or dead leaves. Dig up the rhizomes, those fatty tubers, and cut them with a sharp knife to about 3 or 4 inches long.
Throw away any mushy parts. Don’t compost them. Trim the roots to about 2 inches.
If you’ve had issues with fungal disease, treat your rhizomes with a fungicidal powder and rinse your tools with a 10% bleach solution after each cut to help prevent spreading of disease.
To replant, loosen the soil to about 8 to 10 inches. Even though irises are planted in a shallow hole, this will allow the roots an easier time to grow. Place the rhizome so that it barely sits under the soil, firm the soil and then water it in.
Don’t mulch your iris. They need a dry period. You can mulch AFTER the ground has frozen.
More new introductions for 2022 from breezewayiris. I’m not endorsing them just sharing what’s out there!
