Fothergilla leaves make the transition from green to red in the National Herb Garden at the U.S. National Arboretum. (Photo credit U.S. National Arboretum)

This post is part of the Science Tuesday feature series on the USDA blog. Check back each week as we showcase stories and news from USDA’s rich science and research portfolio.

Like a lot of people, I remember being taught when I was young that the brilliant autumn foliage of deciduous trees was caused by the cold temperatures of autumn frosts.  I believed this until I became a horticulturist, studying the intricate system that plants use to prepare for winter’s harsh weather.  Where I work, at the U.S. National Arboretum, we grow about 10,000 different kinds of trees and shrubs and have an overwhelming variety of fall color right now. Read more »

In honor of Arbor Day, I helped plant a tree at USDA’s National Arboretum on Friday morning, April 29. What made this unique from the thousands of similar tree plantings taking place nationwide today is that I was joined by a visiting delegation of Afghan agricultural experts.

The delegation included agricultural leaders from Afghanistan’s Ghazni Province who are part of an agricultural exchange program hosted by the National Guard Bureau’s Texas Agribusiness Development Team (ADT) IV.  Washington, D.C., is the first stop on a nearly two-week trip to the United States, which will include training and presentations by some of this country’s premier agricultural experts. Read more »

Agriculture Secretary Tom Vilsack (left) and Ambassador Zhang Yesui, People’s Republic of China sign a Memorandum of Understanding to establish a National China Garden at the National Arboretum in Washington, D.C., Monday, January 24, 2011.

Today, I joined China’s Ambassador to the United States Zhang Yesui to sign a Memorandum of Understanding to construct a classical Chinese garden at the U.S. National Arboretum in Washington, D.C. This garden will illustrate the commitment our two countries have to horticulture, science and the arts and will serve as a testament to our countries’ celebrated cultural histories, delighting visitors for generations to come. I was pleased to join Ambassador Zhang and Madame Jiang Zehui to help turn this symbol of bilateral friendship into a reality. Madame Jiang Zehui is the executive director for the Chinese side for the China Garden. Read more »

USDA scientists Susan Bentz and Richard Olsen examine bagged branches of hybrid hemlocks inoculated with hemlock woolly adelgid as part of field tests of the hybrids’ tolerance to the Asian pest.

This post is part of the Science Tuesday feature series on the USDA blog. Check back each week as we showcase stories and news from USDA’s rich science and research portfolio.

For nearly 60 years, a relentless Asian insect with a silly-sounding name–the hemlock woolly adelgid, or HWA–has chomped a deadly swath through 17 northeastern states, portions of Canada and the Appalachian Mountains, literally sucking the life out of native hemlock trees. Read more »