They received responses from over 8,000 UK gardeners who’d just been battling with weeks of unprecedented dry weather and drought. Which plants fared the worst in a heatwave? Per the RHS’ data, the “losers” in extreme heat were:Hydrangea Acer Fuchsia Astilbe Roses Anemone Ferns Heuchera Phlox Crocosmia. The area went without rain for almost six weeks, and gardeners took note of what survived. BBC Gardeners’ World said geums, hardy geraniums, bearded irises, nepeta, sea hollies, and sedums can flourish in dry weather too.