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Research and Design Guidelines

Scientific Principles

There have been several explanations on the restorative benefits of nature by scientists. Three widely accepted theories are:

  • Biophilia Hypothesis

    The term biophilia was first coined by social psychologist Erich Fromm and defined as “the passionate love of life and all that is alive”. The biophilia hypothesis states that people have an innate emotional affiliation to nature and other living beings and hence, derive benefits from contact with nature.

  • Attention Restoration Theory

    A person has several states of attention including directed attention and effortless attention. Directed attention requires effort and is used when concentrating on specific tasks, such as working on the computer. This requires voluntary effort and prolonged usage will lead to directed attention fatigue, resulting in ineffectiveness and human error.

    According to the Attention Restoration Theory (ART), restoration of directed attention fatigue can be derived from the use of effortless attention when a person is in a natural environment. Based on ART, gardens provide an opportunity for people to rest since they do not have to exercise directed attention. They do not have to consciously exert effort to pay attention to their surroundings and this is termed as “effortless” attention. As this state of attention is effortless, it provides an opportunity for us to rest from a state of directed attention.

  • Stress Reduction Theory

    The stress reduction theory states that contact with nature has been shown to reduce stress. People who are sick or caring for the sick tend to experience stress. Hence, green spaces have beneficial effects on patients and care givers through the reduction of stress.



The National University Health System (Yong Loo Lin School of Medicine) and National Parks Board conducted a joint clinical research study to determine if engagement in horticultural therapy improves the mental health and well-being of community-living elderly in Singapore. In the randomised control trial, participants of horticulture therapy engaged in nature-related activities, including gardening and guided walks in various parks.

Based on self-reported changes and objective assessments using biomarkers from blood samples, participants of horticulture therapy showed improvement in mental health and well-being. They showed significant improvements in social connectedness and were found to have reduced levels of plasma IL-6. The latter is a cytokine associated with depression and inflammatory disorders. In comparison, no significant changes were observed in the control group.

Participants of horticulture therapy also maintained their levels of biomarkers that offer protection on neuronal functions (CXCL12, CXCL5 and BDNF), whilst the control group showed decreased levels. Overall, the evidence from the study supported horticulture therapy as an effective treatment that promotes the well-being of elderly in Singapore. Potentially, horticulture therapy may be scaled up as a programme to benefit elderly in senior activity centres.

Three research papers have been published on the study to date:

  1. Ng, K. S. T., Sia, A., Ng, M. K. W., Tan, T. Y C., Chan, H. Y., Tan, C. H., Rawtaer, I., Feng, L., Mahendran, R., Larbi, A., Kua, E. H., and Ho, R. C. M. (2018). Effects of Horticultural Therapy on Asian Older Adults: A Randomized Controlled Trial. Int. J. Environ. Res. Public Health 15, 1705.

  2. Sia, A., Ng, K. S. T., Ng, M. K. W., Chan, H. Y. Tan, C. H., Rawtaer, I., Feng, L., Mahendran, R., Kua, E. H., Ho, R. C. M. (2018). The Effect of Therapeutic Horticulture on the Psychological Wellbeing of Elderly in Singapore. Journal of Therapeutic Horticulture 28(1).

  3. Chan, H. Y., Ho, R. C.M., Mahendran, R., Ng, K. S., Tam, W. W., Rawtaer, I., Tan, C. H., Larbi, A., Feng, L., Sia, A., Ng, M. K. W., Gan, G. L., Kua, E. H. (2017). Effects of horticultural therapy on elderly's health: protocol of a randomized controlled trial. BMC Geriatrics 17(1). doi: 10.1186/s12877-017-0588-z


Design Features of Therapeutic Gardens

The design features of a therapeutic garden include the use of plants to evoke the senses, ignite memories and bring about mental well-being; and universal design for accessibility and other user centric amenities. 

 The gardens offer physical and emotional comfort, providing choices of both serene restorative spaces with an immersive ambience amidst nature, as well as invigorating active spaces with facilities for therapeutic horticulture programmes. Plants that elicit a calming effect are selected for the restorative spaces, whilst those in the active spaces come in warm bright colours to energise the users.

Find out more about the design guidelines for therapeutic gardens.


Last updated on 29 August 2018

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