March 24 (Bloomberg) -- The calls begin for Robert DeFeo on the first warm day in January. When will the cherry blossoms be at their glorious best?

It's DeFeo's job to know. He's the National Park Service's chief horticulturist for the Washington, D.C., region, and the nation's capital is home to what is probably the biggest cherry blossom celebration outside Japan. It starts tomorrow, and runs through April 9.

There's a lot hanging on DeFeo's prediction. Festival goers time their visits to when the blossoms around the city's Tidal Basin are most stunning. Restaurants offer cherry-themed meals and drinks; hotels have special packages. They want to hear that the peak will be on a weekend, when more people can come out.

The blossom period is ``short but sweet,'' said the 50-year- old DeFeo, who isn't ready to give his prediction of the peak -- when at least 70 percent of the trees will be in full bloom -- just yet. Maybe later. Read on.

More than a million people are expected to attend the festival, according to Bill Hanberry, president of Washington's Convention and Tourism Corp. That ranks the event in the top 10 to 15 percent of all festivals worldwide, said Steve Schmader, chief executive officer of the 3,000-member International Festivals & Events Association in Boise, Idaho.

While officials say they don't have figures for the festival's total economic impact, the estimated 360,000 visitors from outside the capital region will alone spend an estimated $133 million, Hanberry said.

Taiko Drummers

The celebration kicks off tomorrow with a kite-flying contest near the Washington Monument and a ``family day'' focusing on Japanese arts and pop culture. A week later, there's a parade down Constitution Avenue with taiko drummers, Cherry Blossom princesses and the National Cherry Blossom Festival's very own All-Star Tap Dance Team, according to the National Cherry Blossom Festival Inc., the not-for-profit group that runs the celebration with 1,000 volunteers and five year-round employees. There will be fireworks, flower-viewing cruises on the Potomac, kimono exhibits and concerts, with activities in all eight city wards.

D.C. restaurants generate more revenue during the two weeks of the festival than at any other time of the year, Hanberry said. Diners can enjoy seared duck breast with a cherry balsamic glaze at Aria Trattoria, chicken potstickers with spicy sweet cherry sauce at Bangkok Joe's and port-soaked cherries at the Caucus Room, a favorite haunt of lawmakers and lobbyists.

Cherry Sugar Scrub

Morton's will be offering ``Cherry Blossom'' martinis (cherry vodka and cherry syrup with a cherry meringue whipped topping) and Zengo features a ``Blushing Geisha'' cocktail of vodka, sake and brandied cherry puree.

Hotel occupancy, normally about 72 percent, jumps to 84 percent during the festival. The Mandarin Oriental, which overlooks the Tidal Basin, is offering a Cherry Blossoms Bloom package, which includes homemade chocolate cherry chunk cookies, for $369 a night, and a Cherry Blossom Bliss spa package, featuring a cherry sugar scrub, for $420.

This all goes back to 1912, when the mayor of Tokyo gave Washington 3,000 cherry trees, mostly of the Yoshino variety, as a symbol of ``the continued close relationship'' between the countries, according to the festival's Web site. The city now has 3,750 cherry trees, including 125 of the originals, the park service's DeFeo says. The festival itself began in 1935 and became a two-week event in 1994.

``Blossom Front''

In Japan, where the cherry blossom is considered a symbol of the transience of beauty and life, viewing the flowering trees is a serious national pursuit, heralded by daily ``Blossom Front'' reports on television. Daylong ``hanami'' parties at places like Tokyo's Ueno Park draw thousands, seating blanket to blanket beneath the trees eating and drinking and, in some cases, reciting appropriate poetry.

``Why, with ceaseless, restless haste/ Falls the cherry's new-born bloom?'' one centuries-old poem concludes.

American blossom viewers may not bring the same spirituality to the occasion, but the park service's DeFeo can wax poetic as well. On the question of how long the cherry blossoms linger, he says: ``When it's warm, they leap. When it's cold, they creep.''

He also compares the stages of a bud's development to a pregnancy and describes the blossom bearers as ``a sexy population of trees.''

Which brings us back to the big question: When will the blossoms peak this year? DeFeo's best guess now, shown on the park service Web site's ``Bloom Watch'' page, is sometime from March 26 to March 28.

He estimates the total blooming season will run from today through April 5, and says people should realize there are other special times within that period. His favorite, he said, is near the end, when the blossoms are falling and it's ``like it's snowing out there.''

Or as the Japanese poet may have said, when the new-born bloom falls with ceaseless, restless haste.

To contact the reporter on this story: Nadine Elsibai in Washington at nelsibai@bloomberg.net

Last Updated: March 24, 2006 00:01 EST