• slide
  • slide
  • slide
  • slide
  • slide
  • slide
  • slide
Iris-Borer.jpg

Iris Borer

Last year I lost most of my irises. The leaves turned brown and the rhizomes were soft and mushy. What caused this and how can I keep it from happening again?

Iris borer is the culprit. This day flying moth lays its eggs in the leaf litter of iris each fall. The eggs overwinter and hatch in spring when the new leaves are about 4 to 6 inches tall. The borer enters the leaf and eats it way through the leaf and into the rhizome where it feeds in early summer. The borer pupates in the soil and in fall emerges as a moth to start the process all over again. Understanding its lifecycle can help with control. Fall cleanup, removing the old iris leaves, may be enough to control this pest. Removing the egg laying site sends the moth looking for a better place to lays its eggs. As you dig and divide iris, remove and destroy any borers that are found. Cut out and discard damaged portions of the rhizome and replant the healthy portions for future blooms. Many gardeners have had success using predacious nematodes to control the borer. These creatures are sprayed onto the plant in spring where they find and parasitize the borer. Check the internet or garden catalogues specializing in biological pest control.

Related

Upcoming Live Events
& Webinars


Feb. 28, 2024
FREE WEBINAR

Create a Beautiful Landscape Free of Invasive Plants in Wisconsin Gardens
Register now

Feb. 29, 2024
FREE WEBINAR

How to Plan Your Rain Garden
Register now

March 6, 2024
FREE WEBINAR

Growing Summer Bulbs in Containers
Register now

March 7, 2024
Help Your Landscape Thrive After Winter

Wauwatosa Public Library, Wauwatosa, WI
Register now

March 13, 2024
FREE WEBINAR

Hydrangea Selection, Pruning & Care
Register now

March 14, 2024
FREE WEBINAR

How to Select Rain Garden Plants
Register now

March 20, 2024
FREE WEBINAR

Maximize the Beauty and Enjoyment
in Any Small Space
Register now

March 23, 2024

REALTORS Home & Garden Show
West Allis, WI

March 27, 2024
FREE WEBINAR

How to Start a Garden for Beginners
Register now

April 3, 2024
Garden Trends 

Franklin Public Library, Franklin, WI

April 10, 2024
FREE WEBINAR

Container Gardening Throughout the Year
Register now

April 11, 2024
FREE WEBINAR

7 Steps to Managing Water Where it Falls in Your Yard
Register now

April 20, 2024
Pruning Hydrangeas and Other Shrubs 
Pasquesi Home & Gardens, Lake Bluff, IL

April 27, 2024
Ridges & Rivers Book Festival
Viroqua, WI

April 28, 2024
Flowering Trees and Shrubs
Ebert's Greenhouse Village, Ixonia, WI

May 1, 2024
FREE WEBINAR

Ornamental Fruits and Vegetables
Register now

WATCH ON-DEMAND WEBINARS

Learn More

Book an Appearance

Learn More

Enter to win Longfield Gardens bulbs valued at $157.00 !

ENTER NOW