The stench of Wisley

Flies, elephants and visitors of a sensitive disposition beware! Cunning plants are spinning stinky tricks in The Glasshouse

If, as you walk into the Tropical Zone of The Glasshouse, you happen to notice a terrible whiff as if something has died, then you may well be close to spotting an Amorphophallus in flower, trying to lure in flies and beetles.

Amorphophallus bulbifer close upAmorphophallus is a genus of plants containing 200 species, hailing from the tropics in Africa, Asia and Australasia. We have seven different species in the Tropical Zone of The Glasshouse.

You can recognise Amorphophallus as part of the aroid family by their inflorescence that consists of a spadex (which actually contains the tiny flowers) surrounded by one large, single, petal-like structure called a spathe. However, unlike most other aroids, Amorphophallus only ever puts out one leaf or one flower a year. The flowers tend to last only a few weeks, but the single, large, divided leaf stays around until late autumn, sometimes even longer.

Probably the most spectacular of all Amorphophallus is the titan arum, (Amorphophallus titanum), which grows to an enormous size - the flower itself can reach more than 3m (10ft) high. At Wisley, ours is only a few years old and stands about 1.5m (5ft) tall, but it is already quite a struggle to shift it! It will be a few years and a lot of growing before we can start hoping for a flower, but there is no way of knowing or controlling whether it will grow a flower or a leaf even when it is big enough. We’ll all have to watch this space…

Come fly with me...

Amorphophallus leaf on left and flower on rightAnd what about the smell? Some Amorphophallus are pollinated by beetles and flies, which are not so interested in nectar or sweet scents. Instead, these plants use the smell of rotting meat to trick the insects into thinking there’s a rotting corpse for them to lay their eggs in. Eurgh! However, the subterfuge doesn’t end there; the plants use a number of traps to hold the insects hostage inside the spathe, keeping them long enough to collect the pollen. Then they let them go, letting them find another Amorphophallus to complete the pollination process. For example, some Amorphophallus flowers have warts or hairs around the spadex, which make it difficult for the insects to squeeze past.

Cunning camouflage

Amophophallus stem showing lichen like patternAnother clever adaptation of some of the species is the pale patches on the stems. This is thought to be a way of the plant protecting itself from elephants and other large African animals, by giving the appearance of having lichen.

The thing with Amorphophallus is that while they get very big, they don’t get strong tree-like trunks and an elephant going for a stroll could easily tread the plant’s one precious leaf into the ground. But if the elephant thinks that the arum is really a tree, due to the lichen growing on it, it will do a detour around the plant. Clever, eh?  It’s just another fascinating part of the natural world.

Anyway, if you are intrigued by the 'interesting' fragrance, come and explore the Tropical Zone, where we’ve plenty to keep your noses, and eyes, busy (you can always go and smell the roses afterwards!).

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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.