The Chelsea Flower Show was Back in its regular slot of May for the first time since 2019, after being cancelled in 2020 and moved to September for 2021 due to the pandemic.The Great Plant Sell-off happens on the final day of Chelsea Flower Show, when polite chaos ensues as the public pick up a bargain in this quintessentially English of pastimes, which also marks the end of Spring and the start of Summer.