By Terri Reddout, Irrigated Agriculture Research and Extension Center

Bill Howell stands next to one of the
usuzumi cherry trees in Washington, D.C.
PROSSER, Wash. – Fourteen hundred years ago, or so the story goes, the emperor of Japan planted a cherry tree in the village of Neo. That tree still stands – more than 50 feet tall and 30 feet in diameter. The ancient “usuzumi” (light gray) flowering cherry tree has survived earthquakes, typhoons and an ant invasion.
A little more than a decade ago, the people of Neo decided their tree’s beauty deserved a wider audience, so they presented the United States with cuttings. Those cuttings were propagated to create some of the more recent flowering cherry trees around the National Mall in Washington, D.C.

Restoring cuttings to health

But before the Neo cuttings took root at the U.S. capital, they were sent to WSU’s Irrigated Agriculture Research and Extension Center in Prosser. Bill Howell was operations manager for IR-2, a predecessor of the National Clean Plant Network for Fruit Trees (NCPN-FT).
“When they came to us, the cuttings were in pretty bad shape,” Howell said. “The budwood sticks were dry and shriveled. But somehow we got them to grow.”
Tests indicated the trees were infected with at least two viruses.
“We had to clean the viruses out of the trees before we could release them to be propagated,” said Howell. That meant putting the trees through heat therapy. It took another three years for the trees to get a clean bill of health.
Eventually they were planted along the Potomac River near the Roosevelt Memorial.
Healthy trees a team effort
On a recent visit to Washington D.C., Howell took some time to visit the trees.
“My kids like to call them ‘Dad’s trees,’” he said. “But it’s the kind of research and science our people do every day at the NCPN-FT, and they should get the credit.”
Those people include Jan Burgess, who conducts heat therapy on plants; James Susaimuthu, who analyzes plants undergoing virus indexing; Elmer Wilcowski, who bud grafts the trees needed for indexing; and Shannon Santoy, who runs molecular diagnostics for plant diseases.
The crew works together to make sure growers can get fruit trees without viruses – and that places like the capital can be graced with healthy, beautiful trees.
“We’ve cleaned viruses out of a lot of new fruit tree varieties planted in orchards all over the world,” Howell said. “But the usuzumi flowering cherry – that really shows what we can do for flowering trees.”
Learn more about the National Clean Plant Network by visiting