Once smelled, never forgotten: the voodoo lily Dracunculus vulgaris has one of the most eye-wateringly awful aromas of any plant. It grows wild on stony hillsides in Greece and Crete, where the stench of its flowers - reminiscent of a decaying sheep carcass, drifts long distances and attracts fly pollinators. It belongs to a group of plants that are known as sapromyophilous flowers, which means that their flowers emit the scent of decay and attract flies. It sprouts from a corm and I've grown it twice. On the first occasion I left it on the living room windowsill for a couple of days while we went away for the weekend and it took us two weeks to get the pong out of the curtains and carpets. On the second occasion, a couple of years ago, I grew the specimen in the photo and planted it outside in the garden just as it was about to open its rather spooky inflorescence. I suspect that the neighbours much have wondered whether something had gone catastrophically amiss with their drains. It's one of those botanical curiosities that you just have to grow once - or if you are a real masochist twice - but that'll do. If you wanted to be really mean and had a tendency towards botanical practical jokes you could send an unlabelled corm to an acquiantance with instructions to grow it indoors. They'll love you for it. There's also another plant marketed under the name voodoo lily, Sauromatum venosum, which has a similar stench but has purple spots on the hood-like spathe and a much longer tongue-like spadix.