HORTICULTURAL THERAPY & THERAPEUTIC HORTICULTURE

Research Database

The Horticultural Therapy / Therapeutic Horticulture Research Database is a comprehensive, organized collection of research studies focused on the benefits, methodologies, and applications of horticultural therapy (HT) and therapeutic horticulture (TH). It serves as a resource for researchers, practitioners, educators, policymakers, and funding organizations interested in evidence-based applications of HT/TH.

Purpose & Intended Users
  • Researchers – Access peer-reviewed studies, case studies, and meta-analyses to support further academic work.
  • Practitioners – Find evidence-based strategies and interventions for therapeutic horticulture programs.
  • Educators – Utilize research findings for curriculum development in HT/TH and related fields.
  • Policymakers & Funders – Review data on program effectiveness to support policy initiatives and grant funding.
  • Healthcare Professionals – Explore intersections between HT/TH and allied health disciplines such as occupational therapy, physical therapy, nursing, social work, and counseling.

To enhance usability, studies are categorized using a structured tagging system. Each study is assigned tags based on:

  • Program Type – Defines the nature of the intervention. 
  • Population Groups – Identifies the target demographic.
  • Setting or Context – Specifies the environment in which the intervention occurs.
  • Health and Wellness Outcomes – Highlights key benefits and effects.
  • Allied Profession Intersections – Indicates related fields that may apply the research.
  • Type of Activity – Describes specific horticulture-related interventions.
  • Evidence Type – Classifies the research methodology.
  • Measurement and Evaluation – Details how outcomes are assessed.
  • Research Source – Identifies where the study originates.
  • Access – Specifies whether the research is freely available or requires payment.

This Tagging Glossary provides clear definitions for each category used in our database, helping you quickly understand and choose appropriate filters. This ensures consistency across the database and allows you to easily locate studies most relevant to your therapeutic horticulture practice.

View Tagging Glossary

The Root in Nature team has carefully selected high-quality research papers, making them easy for you to access. Sign up to explore 10 featured papers and receive new research papers directly in your inbox each month through our Root Beat newsletter.

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Dr. Paula Diane Relf

A Special Thank You to Dr. Diane Relf

This research database was made possible by the generous support and vision of Dr. Diane Relf, a pioneer in horticultural therapy. Her dedication to research and education has left a lasting impact on practitioners, researchers, and students. Learn more about her contributions and the special research collection in her honour.

Learn more about Dr. Relf
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Program Type
Program Types
Population Groups
Population Groups
Setting or Context
Setting or Context
Health and Wellness Outcomes
Health and Wellness Outcome
Allied Profession Intersections
Allied Profession Intersections
Type of Activity
Type of Activity
Evidence Type
Evidence Type
Measurement and Evaluation
Measurement and Evaluation
Research Source
Research Source
Access
Access

Harnessing Nature for Occupational Therapy: Interventions and Health Promotion

The study found that over 85% of park staff and occupational therapists improved their knowledge and confidence in adapting nature-based interventions after completing the course preview or training session​. Additionally, 93% of surveyed occupational therapists reported using gardening or outdoor activities in practice because they were meaningful to clients, confirming the value of integrating nature into therapy settings​.

Greenspace Interventions, Stress and Cortisol: A Scoping Review

The review found that 14 out of 18 studies reported reductions in cortisol levels following green space interventions, especially those involving forest bathing and gardening​. However, over 50% of studies lacked proper timing controls or consistent cortisol collection methods, making it difficult to compare results or draw strong conclusions across the field.

Gardener Well-Being along Social and Biophysical Landscape Gradients

The study found that gardeners in neighborhoods with high urban land cover and low housing opportunity spent significantly more time in gardens—an average of 6.8 hours per week, compared to those in greener areas​. The most frequently reported well-being benefit was access to fresh organic food (58.2%), followed by mental health (36.3%) and connection to nature (23.1%), confirming that gardens serve as essential green spaces in both emotional and practical ways​.

Garden Smellscape–Experiences of Plant Scents in a Nature-Based Intervention

The study found that pelargonium (especially the “Dr. Westerlund” variety) was the most frequently mentioned plant, with participants using its citrus scent to feel calm and reduce stress both during and after the program​. Natural smells were consistently described as triggers for positive emotions and memories, while artificial odors were linked to stress, anxiety, and unpleasant past experiences.

From Evidence to Design Solution—On How to Handle Evidence in the Design Process of Sustainable, Accessible and Health-Promoting Landscapes

The Move Green Nature Trail design process resulted in 37 evidence-based design goals and 65 tailored design solutions, covering everything from accessibility to mental restoration and social interaction​. Features like floating bridges, sensory gardens, and multi-level trails were carefully integrated to create a space that is inclusive, calming, and beneficial for physical and emotional well-being​.

Formulating Evidence-Based Design Guidelines for Therapeutic Gardens Tailored to Elderly Populations: A Synthesis of Reminiscence and Preference Studies

The study found that 82% of active seniors considered gardens essential to their current lives, while 86% of care home residents identified observing nature as the most satisfying garden activity. Participants most frequently named roses, tomatoes, and apples as meaningful plants, highlighting the importance of including familiar species to spark positive memories and emotional well-being.

Foliage Plants Improve Concentration and Emotional Condition of Elementary School Students Performing an Intensive Assignment

The study found that boys who worked near foliage plants increased their task accuracy from 36% to 52.7% and solved an average of 8.2 questions, compared to 5.7 without plants​. Brain activity also showed a significant increase in attention-related markers (SEF50) and a reduction in theta waves, which are linked to lower concentration, when plants were present.

Exploring the Use Of Landscape To Enhance Social Interactions Among The Inmates Of Centres For Destitute Children

The study found that landscape features like therapeutic gardens and communal play areas significantly improved emotional well-being and peer interaction, helping children feel more supported and less isolated​. Centers that included inclusive, sensory-friendly outdoor designs reported higher levels of physical activity, stronger social bonds, and a greater sense of belonging among residents​.

Exploring The Use Of Architectural Elements To Promote Wellbeing Via Social Interaction In Centers For Autistic Children

The study found that centers using natural elements, open layouts, and visual wayfinding tools showed improved social interaction and reduced anxiety among autistic children, compared to those without these features​. International examples showed that sensory gardens, textured signage, and calming spaces increased inclusion and independence, reinforcing the importance of empathetic, child-centered design in autism care facilities.​

Exploring the Relationship between School Gardens, Food Literacy and Mental Well-Being in Youth Using Photovoice

The study found that students who participated in school gardens reported improvements in mental well-being, self-confidence, and emotional resilience, all linked to their hands-on food and garden activities​. Themes of connection, personal growth, and health emerged as powerful benefits, with students feeling more valued, relaxed, and inspired by being part of a safe and inclusive green space.

Evaluation of the Guelph Enabling Garden

The evaluation found that 97% of users rated the garden space as “very good” or “good”, with 82% of participants reporting improved mood after attending events like Tea n’ Tales​. Additionally, over 900 volunteer hours were logged in a single season, reflecting strong community involvement and a shared sense of ownership of the garden​.

Evaluation of the Effect of a School Garden as an Educational Didactic Tool in Vegetable and Fruit Consumption in Teenagers

Students in the food education + school garden group increased their fruit and vegetable intake by 65.2 grams per day, compared to no improvement in the control group​. They also reported higher willingness to eat fruits and vegetables daily (up to 97.5%), and showed a 54.8% increase in calories from vegetables and 32.3% from fruits, highlighting the power of combining classroom learning with hands-on gardening​.
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Dr. Paula Diane Relf

Alexis Ashworth

Naomi Caufield

Audree Beaulieu Asta

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