

Cherry blossoms begin to bloom at the Martin Luther King Jr. National Memorial on the Tidal Basin in Washington, Monday, March 19, 2012. Charles Dharapak/AP
With the Jefferson Memorial in the background, cherry blossoms bloom along the Tidal Basin in Washington, Monday, March 19. Pablo Martinez Monsivais/AP
Khandan Jahanshani of Iran, enjoys the blooming cherry blossom trees among some of the oldest centennial trees along the tidal basin in Washington, Monday, March 19. Jacquelyn Martin/AP
People enjoy the cherry blossoms on the Tidal Basin during the first bloom of the trees in Washington, March 18. This year marks the 100th anniversary of the gift from Japan to the United States. Gary Cameron/Reuters
A cherry blossom bud is seen on a cherry tree that borders the Tidal Basin on March 22, 2011, in Washington. The date when the cherry blossoms reach their peak bloom varies from year to year, depending on the weather. The cherry trees have yet to hit their blooming peak. Carolyn Kaster/AP
Heavy cherry tree blossom buds hang on a tree bordering the Tidal Basin on March 22, 2011, in Washington. Carolyn Kaster/AP
People brave cold temperatures to take photographs of the blooming cherry blossom trees on March 24, 2011, in Washington. Jacquelyn Martin/AP
A Japanese woman who lives in Israel holds fake flowers during an annual Japanese cherry blossom festival at the botanical gardens in Jerusalem on Feb. 25, 2011. Baz Ratner/Reuters
A cherry blossom tree displays the colors of spring at Chua Thien Hau Temple in Chinatown, Los Angeles, on March 9, 2011. Nick Ut/AP
Cherry trees are in full bloom around the Tidal Basin in Washington, with the Jefferson Memorial in the background on April 1, 2010. Susan Walsh/AP/File
Japanese women who live in Israel perform a traditional dance during an annual Japanese cherry blossom festival at the botanical gardens in Jerusalem on Feb. 25. 2011. Baz Ratner/Reuters
The Washington Monument is seen through blooming cherry blossom trees in Washington on April 1, 2009. Jacquelyn Martin/AP/File
The blossoms are almost in full bloom on the cherry trees at the Tidal Basin in Washington near the Jefferson Memorial, background, on March 30, 2006. Ron Edmonds/AP/File
David Karol is silhouetted as he sits in a cherry tree in blossom in Washington on March 30, 2006. Jim Young/Reuters/File
Erika Heikkila of Alexandria, Va., takes a photo of her daughter Karin amongst the cherry blossoms in Washington on March 31, 2009. Gerald Herbert/AP/File
The blossoms are almost in full bloom on the cherry trees at the Tidal Basin in Washington near the Washington Monument, background, on March 30, 2006. Ron Edmonds/AP/File
Cherry blossoms were coated with rain drops on the opening day of the annual National Cherry Blossom Festival in Washington on March 28, 2009. Jacquelyn Martin/AP/File
Tourists walk near cherry blossoms at the Tidal Basin in Washington on March 31, 2009. Larry Downing/Reuters/File
Capitol Hill is seen in the background as cherry trees bloomed on the National Mall on March 23, 2009, ahead of the official start of the National Cherry Blossom Festival. Jacquelyn Martin/AP/File
A tourist's dog walks under cherry blossoms at the Tidal Basin in Washington on March 31, 2009. Larry Downing/Reuters/File