If you want to keep your irises looking spectacular year after year, you’ve got to get comfortable with dividing their rhizomes. It’s not just the best way to get free plants for your garden; it’s actually essential for the plant’s health. Here’s the lowdown on how to do it right.
Why You Should Divide Your Irises
There are two main reasons why you’ll want to get in there and split up those root clumps:
- Propagation: It’s the easiest way to grow your iris collection.
- Rejuvenation: If your older plants have stopped blooming or look a bit “tired,” a good division can jumpstart their vitality.
Dividing for More Plants
Dividing rhizomes is the go-to method for multiplying your irises. Every year, the plant naturally grows at least one new rhizome off the main clump. You can simply snap these new sections off and plant them on their own. By next spring, that fresh little rhizome will be ready to sprout all on its own!
Fixing “Bloom-Shy” Irises
Older irises can sometimes get “lazy” and stop producing those gorgeous flowers. Dividing them gives the plant a second wind. By clearing out the shriveled, woody old sections and keeping only the fresh, firm new growth, you’re ensuring the plant directs all its energy into new shoots and big blooms rather than trying to maintain old, unproductive tissue.
When is the Best Time?
Timing is everything! You’ll want to wait until after the flowering season is over. Pick a day that’s mild—not too scorching hot. Transplanting them well before the fall frost gives the roots plenty of time to get established in their new home before winter hits.
How to Divide the Rhizomes
First, carefully dig up the entire iris clump. A garden fork works best for this—just take it slow so you don’t accidentally chop through the rhizomes or damage the root system. Shake off the excess dirt so you can see what you’re working with.
Now, break the rhizome into individual sections. For the best results, make sure each piece has a healthy fan of leaves and a few good roots attached. This gives the plant a massive head start on rooting and blooming. You can usually just snap the rhizomes apart by hand, but if they’re stubborn, use a sharp, sterilized knife. Try to keep the “wound” or cut surface as small as possible to prevent pests or diseases from moving in.
Replanting Your Irises
Give each new division its own hole in a sunny spot with well-draining soil. Remember not to bury them too deep—irises like to feel the sun on their “backs” (the top of the rhizome). Give them a good soak for the first few weeks to help those roots settle in, and you’ll be rewarded with a beautiful display come spring!
