Thursday, March 31, 2011

Epiphyte Day: The Secret Life of Oncidiums

Onc. cornigerum, Curtis's botanical 1836
-- An April Rainforest Garden Epiphyte Day Post --

My first successful orchid experience (after slaughtering a couple of Phals.) was a Miltassia Charles M. Fitch 'Izumi.' I've written about this plant several times and it continues to be one of my favorites. If someone were to ask me to recommend a first orchid, I would steer them toward something in the Oncidium Alliance.

The genus Oncidium comprises over three hundred species, most of which are epiphytes. The Oncidium Alliance includes related genera like Miltonias, Odontoglossums, and Tolumnias. Oncidiums, at least the ones we see for sale, produce sprays of flowers on long, arching inflorescenses. They want more light than your Phalaenopsis, but can tolerate less light than Brassavolas and Cattleyas. Most Oncidiums are happy in warm temperatures and appreciate a 10-15 degree temperature swing between day and night. They like to dry out between watering sessions, but are forgiving.

For me, the appeal of Oncidiums is the effect created by the mass of flowers crowding an inflorescence. It's a big, colorful show where the whole of the display is more than the sum of its individual flowers. That said, the individual flowers are very cool unto themselves and, like snowflakes, have slight differences in the color patterning. A second advantage of an Oncidium orchid is its lush foliage, providing visual interest all year long. Dark green leaves are an indication of insufficient light. Yellow leaves suggest too much light. Dark spots on the leaves -- speaking from experience -- are usually signs of sunburn, but they could also point to a fungus problem if sunburn isn't a possibility. Finally, many Oncidiums have an amazing scent. The best known of these is probably Onc. Sharry Baby, which gives off an awesome chocolate smell (specifically, Swiss mocha with a dollop of vanilla).

Oncidiums are a perfect starter-orchid because Oncidiums tell the owner in a variety of ways when they’re unhappy. My beloved Brachypetalums show few red flags when they're in trouble; the leave might have a nice gloss while the root system rots away to nothing. Oncidiums, by contrast, are like a Tall Flags Pageantry Corp. When an Oncidium is unhappy the psuedobulbs will wrinkle, the leaves will develop pleating, and the visible roots will start to resemble straw. 

I'm not an expert on Oncidiums, and I only have three (including a de rigeur Sharry Baby) but I think I've discovered a secret to their care: dragging them into the shower. I know some people take their orchids into the bathroom to give them a humidity boost. I propose something a little more radical. I take them into the shower and let them experience a full blast of water. The leaves seem to love it, staying perky all through the dry Midwestern winter. I've stopped worrying about the effect of soap, the heat, and the volume of the water -- it doesn't seem to matter. It's a poor substitute for a rainforest, sure, but it's the best we can do in Zone 5.


James Stapley said...

Nice that your tap water quality is high enough to let you do that; I suspect my tap water would make them look extremely sad. That said, if I had a garden I could just put mine outside sometimes to catch a rain shower or two!

Orchids on a Balcony

CatsandCatts said...

Thanks for visiting!
I should've mentioned something about water quality. There's some county-wide variation here, but our water quality is unusually good (low % of dissolved solids) -- so much so that our big vendor in Kansas City (Bird's Botanicals) uses city water for everything.

Despite our good water, I have a Phrag. that *always* gets reverse-osmosis water from the grocery store. My Paphs get a mix of tap & RO. Everything else gets tap water.