
Everybody has a smell that takes them back to a certain time or place – the oft-cited smell of cut grass, childhood sweets or the first faint waft of the sea on a trip to the beach.
But do we share any common emotional responses to plant scents? Does the smell of lavender always evoke calmness? Do roses stimulate us?
It remains a peculiarly unanswered – or even untested – question in the scientific world and yet if we knew that, the benefits to garden design would be unquestionable.
RHS Wellbeing Fellow
Dr Lauriane Chalmin-Pui hopes to find some answers.

“We know smells are extremely evocative – they take us back to places and memories. This can be enormously beneficial to people with dementia for example.
“The RHS has done so much work on how we can design and plant gardens that are good for wildlife and there is science to back that up.
“Designers know how to create a garden to benefit wellbeing based on their experience and creative ideas. But there isn’t much science to guide how we might optimise this.”
The building of
RHS Hilltop – The Home of Gardening Science and the neighbouring
Wellbeing Garden are the perfect places to start this ground-breaking research.
All visitors to the centre will be offered the opportunity to contribute to the research by interacting with the wellbeing displays. These will explain the premise of the experiment before inviting participants to record their emotional response, if any, to different plant colours and scents.
This experiment has the benefit of potentially capturing data from the thousands of visitors to RHS Hilltop over the next couple of years.

A second, lab-based experiment will also involve volunteers in a more controlled environment for a more in-depth exploration of their responses to plants. That way, Dr Chalmin-Pui can attempt to tease out if responses are provoked by specific memories or not.
“While these will be interesting and important, we want to find out if there is a general response in the population or across different groups of people.
“For most people lavender may turn out to be calming. But not everyone will like it – including myself.”
(As an unimportant aside, I am reminded of clearing a blocked sewer whenever I smell lavender. So I’m not particularly fond of it either.)
For this reason, it is important to capture as diverse a demographic as possible, accurately reflecting all of society.
Encourage good mental health
She also plans to examine if there are seasonal changes in the emotional responses of participants. The five-year-long project is in its very early days, with details still being finalised.
So what could be the end result of this? If we know that certain plants are soothing, joyful, stimulating, or amusing for the majority of the population, then designers can use that to their advantage.
Their existing expertise coupled with the scientific evidence will promote a palette of ideas geared for garden plantings to encourage good mental health for the general population as well as for those in ill-health.
And that benefits everybody.
The influence of gardens on wellbeing

Dr Chalmin-Pui is the RHS Wellbeing Fellow and works as part of the environmental horticulture team, based at RHS Garden Wisley.
She has already completed vital work on the link between gardening and mental health in her PhD examing the impact of front gardens on health and wellbeing.
As well as her research on scent, she is examining how the health and horticultural sectors can work together to maximise beneficial impacts for the UK.
Dr Chalmin-Pui will be sharing her expertise at
RHS Hampton Court Palace Garden Festival.
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