COLUMBUS, OH – March 13, 2026 – The Horticultural Research Institute (HRI), the research affiliate of AmericanHort, has announced $564,521 in research funding for 18 projects in 2026, supporting new work designed to strengthen every stage of the horticulture supply chain. The selected projects address a wide range of industry priorities, including plant propagation and production efficiency, pest and disease management, landscape plant performance, and consumer engagement with horticultural products. Together, the projects reflect the breadth of challenges and opportunities facing growers, landscapers, retailers, and allied businesses. HRI’s investments are guided by four strategic research priorities: quantifying plant benefits, creating innovative solutions, gathering consumer insights, and producing practical and actionable solutions. By aligning funding with these priorities, HRI ensures that supported research delivers meaningful benefits to the horticulture industry. “The projects funded through HRI reflect the industry’s commitment to investing in solutions that strengthen horticulture today and into the future,” said Mark Yelanich, HRI Board President and Research Director at Metrolina Greenhouses. “When businesses and researchers work together through HRI, the results benefit the entire green industry.” Creating Innovative Solutions Lean on me: the roles of microbial "friends" in ameliorating root rot disease in Rhododendron Jean Burns, Case Western Reserve University, Ohio Root rot caused by Phytophthora cinnamomi is a persistent and costly problem in Rhododendron production, often requiring repeated fungicide applications with diminishing returns. This project builds on previous HRI-funded work to identify specific beneficial fungi that naturally help plants survive pathogen pressure. Researchers will evaluate ericoid mycorrhizal fungi and multiple Trichoderma species to determine their ability to improve plant survival and growth under disease stress. By isolating and testing these microbial “friends,” the project aims to identify biological tools that can be incorporated into production systems as alternatives or complements to chemical control. Results will provide growers with science-based guidance on using beneficial microbes to reduce losses, improve plant health, and support more sustainable nursery and landscape production practices. Investigate the rooting-promoting effect of a slow-release synthetic auxin on recalcitrant woody cuttings Haiying Liang, Clemson University, South Carolina Many high-value woody ornamentals are difficult to propagate due to poor or inconsistent rooting, limiting liner availability and increasing production costs. This project will evaluate a slow-release synthetic auxin designed to improve rooting success in recalcitrant woody cuttings. Building on prior HRI-funded work that identified physiological barriers to adventitious root formation, this research will test whether a controlled-release auxin can enhance rooting percentage, root quality, and consistency across challenging species. Outcomes will provide growers with clearer guidance on propagation practices that improve success rates while reducing labor, losses, and repeated hormone applications. The results are expected to translate directly into improved propagation efficiency for nurseries producing difficult-to-root ornamental and woody crops. Transgene-Free by Design: Editing Woody Ornamentals via Agrobacterium rhizogenes-Induced Roots and TLS-Mediated Transcript Mobility Hongmin Qin, Texas A&M University, Texas This project advances a novel, transgene-free genome editing platform for woody ornamentals, using crapemyrtle as a model system. By combining Agrobacterium rhizogenes-induced root transformation with mobile gene-editing transcripts, the research aims to produce gene-edited plants without permanent foreign DNA integration. The approach targets improved cold tolerance while preserving natural pest resistance, addressing two major production constraints. If successful, this system could accelerate precision breeding in woody ornamentals while easing regulatory and consumer concerns. Outcomes will support the development of resilient cultivars adapted to broader climates, providing nurseries with innovative tools to meet future production challenges. AI-enhanced High Fidelity, Multi-stage Nursery Inventory Management of Southern Magnolia Using Intelligent Drones Patricia Knight, Mississippi State University, Mississippi Manual inventory counting is time-consuming, labor-intensive, and prone to error in nursery production. This project will develop an AI-powered drone-based system to accurately identify, count, and classify southern magnolia trees across multiple growth stages. By combining UAV imagery with machine learning models, the system will deliver real-time inventory data through a user-friendly interface. While southern magnolia serves as the model crop, the technology is designed to scale to other ornamental species. Outcomes will help nurseries improve labor efficiency, production planning, and inventory accuracy while laying the groundwork for broader adoption of precision agriculture tools in horticulture. Gathering Consumer Insights Optimizing Digital Marketing Strategies for Horticultural Products: Exploring the Role of AI and Personalization in Consumer Engagement and Sales Juan Mundel, Michigan State University, Michigan As online plant sales grow, horticultural businesses need more effective digital marketing strategies to reach today’s diverse consumers. This project will evaluate how artificial intelligence and personalized social media advertising influence consumer trust, engagement, and purchase intent for horticultural products. Building on prior research showing that culturally and demographically congruent advertising improves outcomes, this study will test AI-driven personalization approaches and disclosure practices. Results will provide growers, garden centers, and retailers with actionable guidance on using AI responsibly to increase marketing return on investment while maintaining consumer trust. Findings will help businesses improve ad effectiveness, strengthen customer relationships, and drive online and in-store plant sales. Producing Practical & Actionable Solutions Exploring effective strategies for managing vascular streak dieback using innovative chemical treatments, biological agents, and nanomaterial-based applications Fulya Baysal-Gurel, Tennessee State University, Tennessee Vascular streak dieback (VSD) has emerged as a serious and costly disease threatening redbud and other valuable woody ornamentals, causing significant plant losses, rejected shipments, and cancelled orders for nursery producers. This project will evaluate and identify effective, practical tools to manage VSD through field-based testing of fungicides, biofungicides, and novel chemical and nanomaterial-based applications. Research trials conducted under commercial nursery conditions will measure disease severity, plant health, and treatment performance to determine the most effective products and application strategies. Results will be translated into clear, actionable management recommendations, including rotation programs, to help growers reduce losses, improve crop quality, and enhance the long-term sustainability of redbud and woody ornamental production. Establishing Micropropagation Systems and Initiating Biotechnological Tools in Redbud (Cercis spp.) Hsuan Chen, North Carolina State University, North Carolina Demand for redbud continues to rise while clean, reliable liner supplies remain limited—particularly due to vascular streak dieback concerns. This project will develop scalable micropropagation systems for popular redbud cultivars and directly compare growth, quality, and performance of tissue-cultured plants versus traditional chip-bud grafted liners. By refining multiplication and rooting protocols using current cultivars, the research will provide growers with validated methods for producing uniform, disease-free liners at scale. The project also initiates biotechnological tools to support future breeding efforts, helping accelerate development of improved redbud cultivars. Outcomes will give nursery producers practical guidance on propagation options, liner sourcing decisions, and long-term strategies to strengthen redbud production capacity and resilience. Using systemic insecticides to protect container grown nursery plants from feeding damage caused by redheaded flea beetle, Systena frontalis, adults Raymond A. Cloyd, Kansas State University, Kansas Redheaded flea beetle adults can substantially reduce the marketability of container-grown ornamentals, resulting in nursery growers relying on frequent, labor-intensive foliar insecticide applications. This project will determine if systemic insecticides applied to the growing medium in containers provides season-long protection against redheaded flea beetle adult feeding damage. Researchers will test several systemic insecticide products under commercial nursery conditions. They will measure effectiveness, residual activity, and plant marketability at the end of the growing season. By identifying treatments that reduce redheaded flea beetle adult feeding damage, this research will lower labor costs associated with applying foliar insecticides and improve management of redheaded flea beetle adults. Results will provide nursery growers with practical, cost-effective management strategies that will allow them to produce marketable container-grown ornamental plants. Accelerating Root Development in Slow-Growing Nursery Stock Using Plant Growth Regulators Kristopher Criscione, Virginia Tech, Virginia Slow root development is a major bottleneck in ornamental production, often extending crop cycles and increasing costs. This project will evaluate whether targeted applications of plant growth regulators (PGRs) can stimulate faster root system development in container-grown nursery stock. By enhancing root fill and quality, plants may reach market readiness sooner or achieve higher quality within standard timelines. The research will assess application methods, substrate interactions, and production impacts under nursery conditions. Outcomes will provide growers with actionable strategies to shorten production cycles, improve liner quality, reduce labor and space constraints, and increase overall production efficiency across nursery and greenhouse systems. Protecting Plant Health: Rapid Molecular Tools for Phytophthora Surveillance in Water Systems Johanna Del Castillo Munera, University of California, Davis, California Recycled and surface water sources can harbor Phytophthora pathogens, posing a major risk to nursery and greenhouse production. This project will develop and validate rapid molecular diagnostic tools to detect Phytophthora directly from irrigation and leachate water. Building on earlier research, the project adapts recombinase polymerase amplification (RPA) assays to deliver accurate results in minutes rather than weeks. Faster detection allows growers to make timely management decisions, evaluate water treatment efficacy, and prevent pathogen spread before losses occur. Outcomes will provide the industry with practical, publicly available protocols to improve disease prevention, reduce crop losses, and support biosecure water management practices. Advancing Integrated Management for the Invasive Box Tree Moth (Cydalima perspectalis) with Biological Control, Cultivar Susceptibility, and Alternative Chemical Strategies Alejandro Del Pozo-Valdivia, Virginia Tech, Virginia Box tree moth is an emerging invasive pest capable of causing complete crop loss in a single season, threatening boxwood production nationwide. This project will advance integrated management strategies by evaluating biological control agents, cultivar susceptibility, and alternative chemical tools under controlled quarantine conditions. By identifying effective rotation options and compatible tactics, the research aims to reduce reliance on limited insecticide groups while improving control reliability. Results will help growers manage regulatory pressures, reduce labor-intensive spray programs, and protect high-value boxwood crops. The project will deliver practical guidance for nurseries and landscapers preparing for or responding to box tree moth infestations. Innovations for sustainable control of high impact bacterial diseases Jonathan Jacobs, The Ohio State University, Ohio Bacterial diseases caused by Xanthomonas and Rhodococcus affect a wide range of ornamental crops and are difficult to manage with existing tools. This project explores innovative biological control strategies using bacteriophages and beneficial Bacillus species as targeted alternatives to traditional chemical bactericides. Researchers will identify, test, and validate biological agents that suppress bacterial pathogens without harming plant quality or the environment. Outcomes will provide growers with new, sustainable disease management options that can be integrated into IPM programs, helping reduce losses, improve plant health, and meet increasing regulatory and consumer expectations for environmentally responsible production. Developing optimized micropropagation and callus regeneration systems for gardenia Wusheng Liu, North Carolina State University, North Carolina Gardenia remains a popular but challenging ornamental to propagate, with limited cutting windows and inconsistent rooting success. This project will develop efficient micropropagation and callus regeneration systems for elite gardenia cultivars, enabling year-round, large-scale liner production. By refining tissue culture protocols, the research will support consistent propagation of high-quality plants while laying the foundation for future trait improvement through biotechnology. Improved propagation systems will help nurseries meet growing demand, reduce production bottlenecks, and improve plant uniformity. Longer-term benefits include expanded market potential for gardenias through improved cold tolerance, rooting strength, and adaptability, giving growers new tools to increase profitability and resilience. Less Suckers, More Profits: Advancing Sucker Management Tools for Ornamentals Marcelo Moretti, Oregon State University, Oregon Sucker and water sprout removal is a labor-intensive, recurring task in field-grown ornamental production, significantly increasing costs and reducing efficiency. This project will evaluate alternative sucker management tools, including plant growth regulators and mechanical approaches, using ornamental Malus as a model crop. Research will focus on identifying safe, effective methods that reduce sucker growth while maintaining plant quality and form. By decreasing reliance on repeated hand-pruning, this work aims to lower labor demands, improve crop appearance, and enhance profitability for nursery growers. Results will generate field-ready recommendations that can be adopted across multiple ornamental species prone to suckering. Silencing the Threat: Develop RNAi-Based Spray Strategies for Integrated Management of Crapemyrtle Bark Scale Hongmin Qin, Texas A&M University, Texas Crapemyrtle bark scale is one of the most damaging and difficult-to-control pests affecting ornamental landscapes and nurseries. This project will develop RNA interference (RNAi)-based spray strategies that selectively silence essential genes in the pest, offering a highly targeted alternative to conventional insecticides. By focusing on species-specific gene suppression, the research aims to reduce pest populations while minimizing impacts on pollinators and beneficial insects. Outcomes will provide the industry with next-generation IPM tools that improve control efficacy, reduce chemical inputs, and lower long-term management costs for crapemyrtle and other affected hosts. Quantifying Plant Benefits Ploidy, pollinators, and plasticity: do polyploid cultivars maintain higher quality under deficit landscape irrigation while still attracting pollinators? Ryan Contreras, Oregon State University, Oregon As water scarcity and pollinator conservation increasingly shape plant selection, growers and landscapers need plants that deliver both performance and ecological value. This project examines whether polyploid cultivars—often developed for sterility and reduced invasiveness—maintain landscape quality under reduced irrigation while still supporting pollinators. Researchers will measure plant performance, water stress tolerance, and pollinator visitation to determine tradeoffs or benefits associated with polyploidy. Findings will help breeders, growers, and specifiers better understand how plant genetics influence resilience and ecosystem services. The results will support informed cultivar selection, helping the industry offer plants that meet regulatory, environmental, and consumer expectations without sacrificing landscape performance. Magnet Plants: increasing pollinator biodiversity via use of non-native, ornamental plants in gardens Gail Langellotto, Oregon State University, Oregon This project evaluates how highly attractive non-native ornamental plants—“magnet plants”—can be used strategically to support pollinator biodiversity in garden systems. By drawing honey bees away from native plants, magnet plants may reduce competition and improve coexistence between managed and wild pollinators. Researchers will measure pollinator visitation, diversity, and behavior in mixed plantings to document ecological benefits. Results will provide evidence-based guidance for growers, landscapers, and retailers on how non-native ornamentals can contribute positively to pollinator conservation. The findings have the potential to reshape consumer narratives, support sustainable landscape design, and expand market opportunities for pollinator-supportive ornamental plants. Stress Relief, Social Bonding, and Consumer Interest Through Plant Gifting and Cooperative Garden Tasks Among Young Adults with Disabilities Xuan (Jade) Wu, Texas A&M AgriLife Extension, Texas This project examines how plant gifting and shared garden activities influence stress reduction, social connection, and consumer interest among young adults with disabilities. By measuring physiological stress, mood, social bonding, and purchase intent, the research will generate evidence-based insights into the wellness and social value of plants. Findings will help garden centers and public gardens develop inclusive, experience-based programming that positions plants as tools for connection and well-being. Outcomes will provide the industry with science-backed messaging and programming ideas that support both community engagement and increased plant sales. The HRI-supported projects will explore solutions to industry challenges, with a focus on sustainability, efficiency, and the overall well-being of the horticultural businesses. As the Horticultural Research Institute continues to support research, the impact of these projects is expected to extend to all segments of the industry. Applications for 2027 research grant funding are being accepted at HRI’s website now through May 31, 2026.

Weed infestations can begin in propagation then persist through the production cycle. Sanitation practices prevent the spread of weeds into propagation areas, while mulches and pre-emergence herbicides are used to suppress weed seed germination and growth during propagation. Explore best management practices for preventing weed infestations in greenhouse and nursery propagation systems. In this session, growers will learn about mulch products and pre-emergence herbicides that can be safely used in cutting and seedling propagation to reduce labor costs associated with hand weeding.