Evaluating Herbicide Treatments to Control Autumn Olive

– Chris Zoller, Extension Educator, ANR, Tuscarawas County

Herbicide applied to Autumn olive August 31, 2023. Photo taken 12 days post-treatment

Autumn olive is a non-native invasive plant that is found in many areas of Ohio, predominately in eastern and southern counties. Originally introduced as an ornamental plant, it has been used for erosion control, windbreaks, and mine reclamation sites. Spread by birds, the plant has disturbed habitats and invaded pastures across Ohio resulting in reduced land for livestock grazing.

A team of OSU Extension professionals is conducting a research trial at the Eastern Agricultural Research Station (EARS) in Caldwell, OH. The EARS facility encompasses roughly 2,000 acres of pasture and woodlands.  Much of the property, 1,325 acres, includes former and active coal mining. The purpose of the research trial is to evaluate various herbicide treatments in the control of Autumn olive.

Winter (Dormant) Herbicide Applications & Results
Our team made six treatments of 30 randomly selected plants on February 15, 2023. The table below summarizes the herbicide application method and use rates.

We returned to EARS on May 25 to evaluate the performance of the herbicides applied to the Autumn olive. Each plant that received an herbicide application was given a rating of 1 (no regrowth); 2 (slight regrowth); 3 (moderate regrowth); or 4 (extensive regrowth).

The table below summarizes the application type, herbicide and rates, and control rating.

Summer (Foliar) Herbicide Applications
The herbicides listed in the table below were applied as foliar applications on August 31, 2023.  A total of 24 plants were treated. The pictures you see above and below were taken 12 days post-treatment.

All products but treatment two in our dormant (winter) applications provided adequate control of Autumn olive.  It is too early to make a true assessment, but our foliar (summer) applications appear to be providing at least adequate control.  Additional evaluation of control will occur in 2024.  Another dormant application of herbicides is planned for February 2024.

Herbicide applied to Autumn olive August 31, 2023. Photo taken 12 days post-treatment.

Study Team
The following OSU Extension professionals are involved in this research project:

  • Alyssa Essman, OSU Extension Weed Science
  • Christine Gelley, OSU Extension Noble County
  • Dean Kreager, OSU Extension Licking County
  • Clif Little, OSU Extension Guernsey County
  • Mark Loux, OSU Extension Weed Science, Emeriti
  • Clifton Martin, OSU Extension Muskingum County
  • Ted Wiseman, OSU Extension Perry County
  • Chris Zoller, OSU Extension Tuscarawas County

Special thank you to the staff at the OSU Eastern Agricultural Research Station for their assistance and support of this project.