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# GTBOP Webinar Archive — Extension Agent Resource

## Weed Control in Ornamentals for the Nursery and Landscape

### Webinar Information

Field | Details
--- | ---
Date | July 13, 2023
Speaker | Dr. Chris Marble, Associate Professor, Ornamental and Landscape Invasive Weed Management, Mid-Florida Research and Education Center, University of Florida
Moderator | Dr. Shimat Joseph, UGA Turfgrass Entomologist
Duration | 50:38
Series | Green & Commercial

### Applicable CEU Categories

Category | Description
--- | ---
10 | Private Applicator
21 | Plant Agriculture
23 | Forestry
24 | Ornamental and Turf Pest Control
27 | Right-of-Way Pest Control
31 | Public Health Pest Control
32 | Regulatory Pest Control
35 | Industrial, Institutional, Structural and Health Related

### Asynchronous Viewing Instructions

This archived webinar is approved for continuing education credit in the categories listed above. For asynchronous CEU delivery, participants should view the complete 50:38 recording and complete any associated assessment activities. The video chapter list below can be used to navigate to specific content segments for review.

### Content Summary

Dr. Chris Marble presents a comprehensive guide to developing weed management programs in nursery production and landscape ornamentals. The presentation covers calibration and application fundamentals, pre-emergent and post-emergence herbicide timing, a systematic three-step process for herbicide selection and rotation by mode of action, and research demonstrating the cost and environmental benefits of combining pre-emergent and post-emergence programs. Marble also reviews alternatives to glyphosate for non-selective post-emergence control and highlights underutilized selective herbicides including graminicides, Basagran, Lontrel, and Certainty. A brief Q&A covers signal words, drift reduction, and Marengo use in nursery non-crop areas.

### Key Topics for CEU Relevance

This session is particularly relevant for professionals managing weed control in ornamental nursery production, commercial landscape maintenance, and right-of-way applications. Topics include herbicide mode of action rotation, the 2017 Southeast Pest Control Guide as a decision tool, label compliance and calibration, research on reducing total herbicide use through integrated pre/post programs, signal word classifications and PPE requirements, and drift reduction strategies. The presentation's emphasis on developing site-specific programs rather than relying on single products supports best management practices across all applicable license categories.

### Video Chapters

0:00 Introduction and Speaker Credentials 0:58 Overview: Weed Control in Nurseries and Landscapes 1:36 Why Herbicides Fail: Calibration and Application 4:34 Calibration Tools and Mixing Calculators 6:35 Pre-emergent Herbicide Timing 8:20 Avoiding Plant Injury During Application 9:29 SureGuard Holly Trial: New Growth vs. Hardened Foliage 10:42 Post-emergence Herbicide Timing 11:30 Environmental Factors Affecting Efficacy 13:18 Stressed Weeds and Mowing Impacts 14:28 Ranking Factors That Impact Post-emergence Performance 15:38 Importance of Developing a Program, Not Just Products 17:17 Herbicide Rotation and Resistance Prevention 18:48 Three Steps to Choosing Herbicides 19:17 Pre-emergence Options Color-Coded by Mode of Action 20:48 The 2017 Southeast Pest Control Guide 21:00 Step 1 Example: Labeled Options for Container-Grown Gardenia 22:02 Grouping Herbicides by Mode of Action 23:01 Step 2: Targeting Primary and Secondary Weed Species 25:20 Step 3: Building a Year-Round Rotation 27:03 Year-Round Nursery Rotation Plan by Month 27:34 Research: Pre-emergent + Post-emergent vs. Post-Only Programs 30:44 Cost Savings and Herbicide Reduction Results 31:55 Application Interval Considerations 32:09 Landscape-Specific Rotation Planning 33:52 Timing Examples: One, Two, or Three Applications Per Year 35:20 Generic Landscape Rotation Example by Season 37:01 Post-emergence Alternatives to Glyphosate in Landscape Beds 38:08 Glufosinate (Finale/Cheetah) as an Alternative 38:43 Non-Selective Alternatives: Desiccant-Type Herbicides 40:12 Acetic Acid Trial: Burndown and Recovery Results 42:23 Selective Post-emergence Options for Landscape Beds 43:04 Graminicides: Underutilized Grass-Selective Herbicides 43:55 Basagran, Lontrel, Certainty, and Scepter 44:44 UF Mid-Florida REC Resources and Contact Information 45:52 Q&A: Signal Words and PPE Requirements 48:02 Q&A: Wind Drift and Reducing Spray Drift 49:08 Q&A: Marengo for Nursery Gravel Areas

### Additional Resources

- 2017 Southeast Pest Control Guide for Nursery Crops and Landscape Plantings — Free download or ~$20 hard copy from NC State. Contains herbicide efficacy and ornamental safety charts referenced throughout the presentation.
- UF Mid-Florida Research and Education Center — Dr. Marble's faculty page with free calibration calculators, weed ID resources, and publications.

Part of the Getting the Best of Pests (GTBOP) Green & Commercial Webinar Series UGA Center for Urban Agriculture / GTBOP Archives