Holiday Crop

December 21, 2012

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When it comes to the top crops of the holiday season — Christmas trees and poinsettiasNorth Carolina is a leader. The state is second nationally in the production of both festive firs and fiery flowers

As one of three university sites in the National Poinsettia Trial, NC State has a significant connection to North Carolina’s poinsettia industry, which produces 4.4 million plants per year. As part of the trial, NC State’s Horticultural Field Lab grows 25,000 plants each year and helps dealers, growers and brokers identify the best breeds for cultivation year-in and year-out, said John Dole, head of the department of horticultural science.

The trial reviews 97 varieties of poinsettia, rating them on height, color, how fully plants branch out and other factors. The trial’s findings inform industry-shifting decisions about what types of poinsettias to grow and market, Dole said.

Given the university’s agriculture and extension missions, a close link with North Carolina’s poinsettia business makes sense. The bond is a solid one for other reasons, too.

“Red and white are NC State colors,” Dole said. “So it’s a natural fit for us.”

Dole has been studying poinsettias for nearly 30 years. His doctoral work helped explain a poinsettia mystery that contributes to the plant’s popularity. Typically, breaking a flower’s stem causes a plant to shoot off with one or two branches, Dole said.

But several decades ago, researchers in Norway discovered that, when certain poinsettia varieties have their stems broken, they branch in all directions, from the base of the stem to the point of the break. That abnormal branching is why a single poinsettia plant can yield enough brilliant bursts of red and white leaves to fill a pot to overflowing, Dole said. Dole identified a bacterium that causes that proliferation; that microbe is now bred into many poinsettia types.

“The fact that this microbe is in the plant has helped turn it into a multimillion-dollar business,” Dole said.

Poinsettias are generally pretty durable, Dole said. With proper care, they can last up to two months, just long enough to be part of a Valentine’s Day arrangement.

“What we recommend is a nice, bright location that can be a little bit on the cool side, if possible,” Dole said. “The best thing is just to avoid sticking it where it’s really dark or really hot.”