A friend of mine was talking about fragrant orchids with her aunt who concluded that she “didn’t know of any that smelled nice, or like much of anything at all.” Well, the aunt is actually incorrect, but I understand why she would feel this way. Most hybrids in the local flower shops were bread for beauty – not for fragrance. So it would seem a logical conclusion.
By estimation about 75% of all orchids are ‘fragrant’. Meaning, they emit some chemical compounds that ‘smells’ – some smell very nice while others reek!! Orchids are the most evolved family of flowering plants in the world and their reproduction amount to a well orchestrated and extremely specialized con-game where scent plays a crucial role.
So weather the scent would qualify as a fragrance or an odor, well… that depends on who the orchid is trying to woo.
Everything about the orchid flower is tailor-made to attract the one specific type of pollinator. While most orchids provide some form of reward for the pollinating services, some are much more deceptive. Instead of luring the suitor with sweet nectar or pollen, some orchids mimic a horny female both in appearance and scent.
In fact… they do it so well that controlled experiments have shown that males insects, intoxicated with fake pheromones, actually prefer the flower over the real deal. (The Ophrys genera are such orchids. Photos courtesy of Wikipedia.)
Research have also shown that scent production is triggered by light. The inflorescence detects whether or not there is daylight and schedules scent production for when it will be the most effective. For example, almost all of the African genera (Angraecum and Aerangis) are moth-pollinated. So these orchids are most fragrant at night when the moths are active.
Other orchids actually change fragrance over the course of the day to maximize the desired effect… Clowesia rosea smells of Vicks vapo rub in the morning and cinnamon in the afternoon. Assuming that the bee, after getting over its cold, might be craving something sweet…
I am currently waiting to see what my Angraecum florulentum will smell like (the flowers need to mature some more first). It is supposed to have a very sweet nocturnal smell. Most Africans smell of lovely night bloomers such as jasmine, honeysuckle, lilies etc.
But I also have a beautiful Bulbophyllum Louis Sander (see large photo above) that smells of week old gym socks, but thankfully the scent is not very strong. But there are much worse to be found among the fly-pollinated orchids. If the pollinator normally feasts on rotting cadavers you can only imagine what the flower smells like…
Luckily more than half of the orchids in the world are pollinated by insects like bees and wasps. Since these little guys are attracted to pretty things the flowers mimic colorful and nice smelling flowers – such as roses, hyacinths and violets.