Gardening: Raising exotic orchids in Philadelphia requires ingenuity

by Stan Cutler
Posted 2/5/21

It takes a particular sort of person to keep tropical plants alive in Philadelphia.

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Gardening: Raising exotic orchids in Philadelphia requires ingenuity


The giant hawkmoth of Madagascar is a bizarre creature, famous for its foot-long proboscis. It’s discovery in 1882 was a scientific moment akin to the measurement of starlight in 1919 that proved Einstein’s theory of curved space. The capture of the moth proved Darwin’s theory that races of plants and animals evolve in relationships with each other.

In 1862, a friend sent Darwin a couple of orchid specimens (angreacum sesquipedale) that had foot-long pollen sacs descending from the flowers with tiny pools of nectar in the bottom. Darwin had no doubt that there was a moth in Madagascar with a proboscis long enough to reach the nectar.  His prediction was dismissed, even ridiculed, by many in the scientific community. Twenty years later, in the habitat where the orchids grew, the giant hawkmoth with the insanely long tongue was discovered. 

My wife, Valerie, cares for a specimen of the weird orchid. She likes the one she’s holding in the picture because it’s strange, not because it smells nice or is exceptionally pretty. In fact, she finds the scent unpleasant. I have olfactory challenges and can’t detect its scent at all.

The sesquipedale  is the only angraecum  with the extended pollen sac. Normal ones, like the angraecum eburneum  over her head in the picture, have a strong, sweet fragrance that even I can smell.  The inflorescence – what orchidists call a stalk with multiple flowers – is coming from the pot next to her in the picture. For obvious reasons, the common name for angreacum is “star orchid”.   

I can’t blame you if you are annoyed by the Latin words. When Valerie first started collecting orchids, I was put off by the insistence on using Latin names by the people who were selling or collecting the plants. I thought it was pretentious. Now, the names are one of the reasons I pay attention. It’s fun to say words like “angraecum sesquipedale”.   And it’s necessary because the orchid family is vast, with tens-of-thousands of named species and varieties.

I am of the generation who took Latin in junior high school. I am terrible at languages, barely passing Latin, switching to Spanish after two years.  I was bad at that, too. But I learned enough to recognize a few patterns, some vocabulary, the parts of speech, the sounds. I have found it helpful, one of the reasons books don’t intimidate me or travel frighten me. Learning new words is also to think about meaning. If we stop asking “what’s that called”, we stop learning. Early learning is the scaffold of lifelong learning; Latin is a strut in the scaffold.

Valerie’s two varieties of angraecum  are among her treasures, plants that have flourished in her orchidarium, her tiny seven-by-twelve plastic greenhouse. The old furnace failed in mid-December. She brought the dozen plants that were budding into the kitchen. She plugged two electric space heaters into the orchidarium’s electrical outlets. She ran out the back door to check the temperature in the orchidarium at least eight times a day.  Last week, mid-January, she finalized replacing the heater, moving thermometers, recalibrating thermostats, repositioning the fans to circulate the heat on cold winter nights. The climate controls had to be repositioned because the new furnace emits heat in a different direction than the old one. 

It takes a particular sort of person to keep tropical plants alive in Philadelphia. The one I married, to put it mildly, is detail oriented. Philadelphia orchids have to live in a tropical bubble. Were the plants to freeze, they would die. If they are uncomfortable, they don’t flower. As small as it is, her orchidarium has different climate zones, low and high, north and south, warmer and cooler, sunnier and darker.  Season by season, noticing slight changes in plant health, she rearranges the pots.  In the warm months, she moves them outside, under the shade of the maple trees. She thinks all of that is great fun.


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