A few years back we stacked old diesel tires, two high and five long, along the edge of our parking area to keep visitors from backing their cars up in that particular spot. We painted the old tire barn red and filled them with ditch dirt. We got tired of watching the weeds grow in them and finally decided to plant Irises. Each stack has a unique color planted in it. Here are some blooms from last spring …
Irises produce rhizomes that multiply and spread and eventually crowd themselves out of small places (like the inside of the tires) to the point that they no longer produce flowers or bloom. In our 7b, Irises are to be ‘thinned’ in January every few years or so. It’s time.
To thin Irises, I dug up the rhizomes, they were clumped. I broke apart each ‘clump’ at the joints to leave smaller, individual rhizomes. Healthy rhizomes are plump with many roots extending from it and have some new leaf growth. I kept the healthy rhizome and threw the rest in the compost pile. To rejuvenate the bed I loosened the soil to remove weeds, stick, and rock, then mix in fresh topsoil. I chose only a few of the healthiest rhizomes for replanting.
To replant an Iris I dug a hole deep enough for the roots to go straight down into the soil and then tamped them in well. The rhizome, however, sets at soil level and isn’t buried. Rhizomes don’t grow under the soil, but just at its surface. Once the Iris are planted a person should still be able to see the rhizomes and new leaves, only the roots are under ground. I covered the newly planted Irises with fallen leaves to help protect them from cold temperatures while the roots establish themselves. I’ll have to move the leaves in about a month, though, to let the spring sun warm the rhizomes. Iris rhizomes need the sun to produce flower shoots and will not produce without it.