Dr Mark Gush

Mark leads the Environmental Horticulture team conducting scientific research into practical interventions that gardeners can apply to reduce their gardening footprint and improve environmental health and human wellbeing

What do you do?

I support and guide a team of scientists and technicians with expertise in plants, water, soils, climate change and human wellbeing. Our research focuses on how to adapt to, and mitigate against, a changing climate, while gardening in a healthy and environmentally sustainable way. We strive to do research that is relevant and impactful, and which addresses important environmental challenges impacting gardening and horticulture today, including weather extremes, inefficient and unsustainable exploitation of resources, pollution and general loss of ecosystem health.

“A career in science is challenging and dynamic. The mental stimulation, potential for positive impact and the variability in day-to-day activities and projects, provide inspiration for someone inquisitive like me.”

Why is your team’s research important?

We depend on, and are influenced by, the natural environment. However, due to the sheer number of humans and our behaviour we also impact that environment hugely, and it is changing as a result. Yet there are plenty of relatively simple actions we can take to reduce or mitigate our impacts and make a positive difference to the world. Many of these are directly linked with environmentally sound gardening practices. Given the substantial number of gardeners in the UK, the cumulative impact of our actions has the potential to make a significant change for the greater good.

Relevant research on environmental horticulture is critical in order to test and refine practical interventions that will allow UK gardeners to contribute to mitigating negative environmental change and human health, in the back garden and beyond.

Projects I’m working on now

Within the broad remit of environmental horticulture, specific areas of interest within the team include:

  • Soils: Organic matter, soil health and nutrients, carbon storage, living fertilizers, soil microbial and biological activity, and soil analysis
  • Plants: Ecosystem services such as cooling and insulation, flood mitigation, air quality improvement and noise reduction
  • Water: Storage (above and below ground), drainage, optimal watering strategies, appropriate technologies and approaches, and improved water management in gardens
  • People: Gardening and plant choice for human health and wellbeing

Completed projects

  • A 3-year Knowledge Transfer Partnership (KTP) project, in collaboration with Cranfield University, on water management in gardens. Project roles comprised company supervisor, partnership facilitator, and proxy manager of the KTP project associate, Janet Manning. Contributed towards the outputs and outcomes of the project, including an RHS water policy, a water road-map for RHS Garden Wisley, a stand at the 2021 RHS Chelsea Flower Show Discovery zone (Water the way nature intended: Switch from mains2rains), and a water-saving pledges website

Prior to joining the RHS in 2018:

  • For more than 20 years, I worked as a scientist and research group leader of hydrosciences with the Council for Scientific & Industrial Research (CSIR) in South Africa, specialising in vegetation water-use, land-use hydrology and water resource management within the agricultural and forestry sectors
  • I completed diverse projects in the measurement and modelling of plant water-use and growth, irrigation-use efficiencies and water footprints of agricultural crops (particularly commercial fruit tree orchards), the water-use and water productivity of trees (including natural forest species, introduced plantation tree species and invasive alien plants), and the hydrological impacts of land-use change


  • Since joining the RHS my focus has been refining the strategic plan for the Environmental Horticulture team, managing the newly formed group, and supporting the team in their respective projects.
  • Contributed towards the launch of the RHS Sustainability Strategy in September 2021, as co-author and team leader on the Net Positive for Nature Target 4 (Water Neutral by 2030) and co-reviewer of the final strategy document.


  • Gush MB. (2021) Hydrological services of fruit trees in gardens and urban horticulture. Acta Horticulturae, 1331: pp245–52
  • Poyatos R, Granda V, et al.…Gush MB. (2020) Global transpiration data from sap flow measurements: the SAPFLUXNET database. Earth Systems Science Data
  • Blanuša T, Qadir ZJ, Kaur A, Hadley J, Gush MB. (2020) Evaluating the Effectiveness of Urban Hedges as Air Pollution Barriers: Importance of Sampling Method, Species Characteristics and Site Location. Environments, 7 (81): pp1–21
  • Gush MB, Dzikiti S, van der Laan M, Steyn M, Manamathela S, Pienaar H. (2019) Field quantification of the water footprint of an apple orchard, and extrapolation to watershed scale within a winter rainfall Mediterranean climate zone. Agricultural and Forest Meteorology, 271, pp135–147
  • Gush MB. (2017) The potential of Vachellia kosiensis as a dryland forestry species in terms of its water use, growth rates and resultant water use efficiency. Southern Forests: A Journal of Forest Science, Vol 79, Issue 3, pp227–234
  • Gush MB, de Lange WJ, Dye PJ, Geldenhuys CJ (eds). (2015) Water use and socio-economic benefit of the biomass of indigenous trees (Vol 1): Research Report. Water Research Commission Report No. 1876/1/15, Water Research Commission, RSA
  • Gush MB, Taylor NJ (eds). (2014) The water use of selected fruit tree orchards (Vol 2): Technical report on measurements and modelling. Water Research Commission Report No. 1770/2/14, Water Research Commission, RSA
  • Gush MB. (2010) Assessing hydrological impacts of tree-based bioenergy feedstock. Published in Amezaga JM, Boyes S, von Maltitz G (eds) Assessing the sustainability of bioenergy projects in developing countries: A framework for policy evaluation, Newcastle University Press, pp37–52. (ISBN 978 9937 8219 1 9)
  • Gush MB, Dye PJ. (2009) Water-use efficiency within a selection of indigenous and exotic tree species in South Africa as determined using sap flow and biomass measurements. Acta Hort, (ISHS) Vol 846, pp323–330. (ISBN 978 90 66056 82 4)
  • Gush MB, Scott DF, Jewitt GPW, Schulze RE, Hallowes LA, Lumsden TG, Görgens AHM. (2002) A new approach to modelling streamflow reductions resulting from commercial afforestation in South Africa. Southern African Forestry Journal, Vol 196, pp27–36

PhD Students

  • Co-supervisor to PhD student Tatenda Mapeto who is researching Water balance processes in indigenous and introduced species tree production systems in Sothern Cape region of South Africa at Nelson Mandela University, South Africa

Get involved

The Royal Horticultural Society is the UK’s leading gardening charity. We aim to enrich everyone’s life through plants, and make the UK a greener and more beautiful place.