Sam Leonard

Sam Leonard is a PhD student studying and quantifying resistance to honey fungus in a variety of horticulturally important plants, using both practical techniques and new molecular techniques

What do you do?

I am a PhD student studying under Dr Jassy Drakulic, in partnership with the University of Reading and Bartlett’s Tree Experts. My studies focus on pairing traditional pathological techniques with new molecular techniques to measure the damage caused by honey fungus (Armillaria mellea) to a multitude of woody plant species commonly found in gardens across the UK. 

My work builds on previous RHS studies by investigating differences in resistance between species in the same genus, which I hope will help gardeners to find alternative plants that they can use in their garden to minimise the spread of honey fungus.

“I hope to help gardeners understand more about how plants respond to honey fungus, so that they can better manage the spread of the disease whilst maintaining the health and appearance of their garden”

Why is your team’s research important?

The Plant Health team at RHS Garden Wisley is vital in helping to identify the pests and diseases that threaten a wide variety of plants across the nation. Honey fungus is a difficult disease to diagnose, and even more difficult to remove from both the infected plant and its surroundings. 

The work performed by the Plant Health team is crucial in preventing further damage to gardens affected by honey fungus. Our team hopes to find new ways to identify honey fungus infection before it spreads too far, and we hope to determine which plants are strongest against the disease. By determining how different species of plants respond to Armillaria infection, we hope to be able to advise gardeners on which plants they can use in their gardens to minimise the damage caused by honey fungus, whilst preserving the look of their garden.

Our team also strives to improve the ways we identify and study fungi in a laboratory setting, in the hope that this will help gardeners to recognise the symptoms of Armillaria infection.

Projects I’m working on now

  • Identifying species-level differences in resistance to Armillaria mellea in different Ligustrum (privet) species
  • Updating existing resistance databases with quantifiable data obtained using a combination of physical markers and molecular techniques
  • Optimising extraction and replication of fungal DNA extracted from the roots of different plant species

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.