It's not too late to tend to your irises

Q: Do you think it’s too late in the year to divide a bed of iris I have growing? It’s four years old, and the plants look crowded. — N.K., Albuquerque

A: Usually the time of year in these parts to divide and replant a bed of iris is July. The iris have finished blooming, and had enough time to refeed the rhizomes preparing for next years’ bloom cycle.

This year, July was so remarkably hot. I couldn’t get out to take care of my grounds without a sincere internal fight because it was so ridiculously hot.

Anyway, yes, if the bed needs decrowding, then go for it.

The finest tool you’ll want to have will be a pitchfork. Impale the fork at the outer edge and lift clumps of the iris. By using the fork, you’ll be less likely to damage the roots and rhizomes of the iris. Using a spade or a shovel, you might shear the roots and perhaps damage the plant parts below ground. A pitchfork is the tool of choice for this project.

Once you’ve lifted the clumps, you’ll want to glean through them. Knock off as much soil away from the plants as you can and pour it back into the bed. While doing that part of the project, inspect the soil for any pests living in the soil. You can collect any grubs you might find in an old coffee can and pitch them when you’re done. Watch for any good earthworms and keep them in the dislodged soil that is going to make its way back to the bed.

You’ve knocked off as much of the soil as you can and now have a collection of plants that have tangled roots, white “feet” and green strap leaves. Using a clean, sharp pair of scissors or handheld loppers, trim the roots of the iris. While you’re trimming the roots, look for plants that can and need to be separated. Usually you can literally snap a young iris away from “mom.” You’ll want to be sure that the youngster has some roots dangling, so be watchful.

Next, tidy the leaves that’ll show above ground. Cleanly snip off any spent leaves without injury to the plant. I like to trim the green leaves, so they look like an arrow pointed away from the base of each plant. You can trim straight across, but whatever look you want, leave several inches of stout green leaf on each plant.

Once the collection is separated and made tidy, set them, out of the sun, somewhere to “dry” while you tend to the bed. You’ve poured all the collected soil back into the bed and should consider adding some fresh compost or garden (top) soil to that space. Give that area a good turning, incorporating the fresh amendments. Break up any large clumps of soil while you’re at it, too. Rake the area smooth and get ready to replant the iris bed.

Invest in some dusting sulfur, disposable gloves and consider a dust mask. Pour some of the dusting sulfur into a paper bag adding a good handful of the tidied iris rhizomes and do a “Shake ’N Bake” type of movement. The goal is to cover the rhizomes with the sulfur since it’ll act as a pesticide/fungicide, keeping the iris healthier in the long run. This part of the project is stinky and very dusty, so don’t do it anywhere or any time it’s windy.

As you pick the rhizomes out of the dust, plant them in the prepared bed. Your aim is to bury the roots and the white “foot” of each one, keeping the green leaves above ground. It’s a fine line, but as long as you don’t overthink it, you’ll gain confidence knowing just how deep to plant.

Since you’ve separated the iris, you’ll have more, so it’ll be a good time to work the extra into a new bed, amongst other perennials you might have growing or give them away. Don’t be stingy with the replanting either, as a single iris looks so lonely. Groups, spaced a bit apart is a good look. Once you’ve gotten the bed or beds replanted, offer a gentle shower to help settle them.

In a few days, a good watering will be in order so the roots wake up a bit and grab hold of the area. Remember to water the bed throughout the dormant months unless we’re blessed with precipitation, and the iris should get their ducks in a row and be ready to bloom for you next spring. Dividing an established iris bed is work, but the satisfaction gained far outweighs the effort.

Go for the dividing now, just don’t wait much longer this season.

Happy Diggin’ In!

Tracey Fitzgibbon is a certified nurseryman. Send garden-related questions to Digging In, Albuquerque Journal, 7777 Jefferson NE, Albuquerque, NM 87109, or to features@abqjournal.com.