We head behind the scenes at Wisley to find out what RHS scientists are studying in their ongoing work to keep our beloved garden plants safe and healthy. And with just a few weeks to go until the ever-popular People's Dahlia Competition at the Wisley Flower Show, we get some top tips on how to get the best from these colourful flowers. Back in the science department, Dr Hayley Jones shares some wisdom on wasps and pathologist Matthew Cromey gives an update on ash dieback and what gardeners can do about it. For more info and useful links see www.rhs.org.uk/podcast