Ryan Hill

Ryan Hill

Agronomy & Weed Sciences Advisor

M.S. Horticulture / Plant breeding and genetics, Oregon State University. 2020
B.S. Biology, George Fox University. 2014
Weed management in orchards and forage crops.

Peer-reviewed publications:

Davy, J., Hill, R.J., & Forero, L. (2025). Herbicide Applications in California Dryland Perennial Grasses Improve Forage Yield and Crop Coverage. Rangeland Ecology & Management, 103, 78-82. https://doi.org/10.1016/j.rama.2025.07.009

Hill, R.J., Nackley, L., Moretti, M.L. (2025). Mustard Seed Meal and Mulches for Weed Control in Greenhouses. Journal of Environmental Horticulture, 43(1), 41-48. http://doi.org/10.24266/0738-2898-43.1.41 

Hill, R.J. & Moretti, M.L. (2024) Herbicide Formulation Affects Weed Control and Crop Tolerance in Greenhouse Ornamentals. HortScience, 56(11), 1629-1633 http://doi.org/10.21273/HORTSCI18159-24 

Hill, R. J., King, D. R., & Moretti, M. L. (2024). Evaluating tiafenacil and tolpyralate for weed control and basal foliage removal in hops. Crop Science, 64(6), 3541-3551. https://doi.org/10.1002/csc2.21322 

Hill, R.J., King, D.R., Moretti, M.L. (2023). The prevention of injury to hazelnut trunks. Acta Horticulturae. 1379, 499-502.  

Hill, R.J., King, D.R., Zollinger, R., Moretti, M.L. (2021). 1-Naphthaleneacetic Acid (NAA) Reduces Sucker Growth in European Hazelnut (Corylus avellana L.). HortScience, 56, 1594–1598. https://doi.org/10.21273/HORTSCI16176-21 

Hill, R. J., Baldassi, C., Snelling, J. W., Vining, K. J., and Mehlenbacher, S. A. (2021). Fine mapping of the locus controlling self-incompatibility in European hazelnut. Tree Genet. Genomes 17:6.

UC Weed Science (weed control, management, ecology, and minutia): Article

What pre-emergent activity does rimsulfuron have on established johnsongrass?

September 17, 2025
By Ryan Hill
To provide better recommendations on how to best use rimsulfuron and other residual herbicides to target johnsongrass I established a set of trials in Shasta and Tehama county prune and walnut orchards in winter and spring of 2025. I had two primary goals: first, to test if early spring rimsulfuron…
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Pollinator habitat coverage in response to herbicide treatments
UC Weed Science (weed control, management, ecology, and minutia): Article

Weed control during pollinator habitat establishment.

May 20, 2024
By Ryan Hill
Introduction: Pollinator insects are essential to produce many economically and nutritionally important crops grown in the western USA. These crops include blueberries, almonds, sunflowers, cucurbits, and many others.
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Figure 3: External (top photo) and internal (bottom photo) injury was measured in unshielded and painted hazelnut trunks, showing a reduction of injury in painted trunks. The trees pictured were sprayed with 224 fluid ounces per acre of glufosinate (4x the legal label rate).
UC Weed Science (weed control, management, ecology, and minutia): Article

Protecting hazelnut trunks from herbicide injury

January 29, 2023
Sucker control in Oregon hazelnut orchards is a season-long struggle against the tree's natural growth habit. Hazelnut trees grow naturally as a multi-stemmed bush, but in Oregon, hazelnuts are trained as a single-trunk tree to facilitate mechanical maintenance, harvest, and reduce pathogens.
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