Prevent Iris Borer
Act now to prevent iris borer from infesting your iris plants and ruining their beautiful floral display.
The iris borer adult is a day flying moth. It lays its eggs in the leaf litter of iris plants each fall. The eggs overwinter in the leaf debris and hatch in the spring when the leaves are about 4 to 6 inches tall. Fall cleanup, removing the old iris leaves, is often enough to control this pest. Removing the place they prefer to lay their eggs sends the moth looking elsewhere.
Continue to monitor this pest throughout the growing season. Watch for streaks running down the leaf that indicate the borers have entered and are feeding in the plant. Pinch the base of the streak to kill the borer.
In summer, dig any borer-infested iris plants. Cut away damaged and rotten portions of the rhizomes and replant healthy sections for future blooms.
A bit more information: You’ll have the greatest transplanting success if you wait at least 6 to 8 weeks after flowering to dig and divide iris. You may choose to wait for temperatures to cool to reduce transplant shock. For tips on digging and dividing iris, click here.