Shaking the dirt from their leaves, 450,000 tulips are working their way out of the ground, ready to paint Washington's parks and public places over the next two weeks with bright strokes of yellow, red, pink and white.

That's only a small part of the annual flower show in the nations capital. The tulips will be accompanied by 1.2 million daffodils and 250,000 hyacinths, crocuses and other small border plants, then followed by 130,000 marigolds, begonias, petunias and geraniums, and finally by a round of 18,000 bronze, yellow and white chrysanthemums in the fall.

The National Park Service will spend nearly $14 million this year -- or 20 percent of its budget -- on its floral extravaganza here. That will include salaries for 18 horticulturists, 90 foremen and gardeners and 75 laborers, who plant, fertilize and maintain the flowers. The Park Service grows no flowers of its own, but instead buys plants and bulbs from area nurseries who bid for the flowers contracts.

Planning for the downtown display began last year in the drab office of Van Brady, the National Park Service maintenance supervisor who is reponsible for all the major downtown parks. Brady and cheif horticultural James Lindsay decide which colors and what flowers will go where in the heart of Washington.

Brady's gardens, however, have some thorny problems.

For instance, he can't plant geraniums in Farragut Square. "If you put them in, the squirrels eat them up." But the red and pink flowers thrive three blocks away at McPherson Square.

But he can't plant begonias at McPherson Square because there the birds eat them. "You go up there some morning and people have thrown corn and 15 loaves of bread out there and there are a million little feet around and they pick the leaves with the crumbs," Brady said.

A block to the east at Franklin Park, dainty impatiens or petunias don't stand a chance against the winos and the Frisbee players.

So thick-stalked, red cannas go in there because "if they are broken [by winos falling into the flower beds] they fill in," Brady said.

Hardy little marigolds are planted at Dupont Circle because they spread to cover bare spots created by running dogs.

Quietly and slowly, some flowers -- chrysanthemums, roses and azaleas -- are fading from the floral fronts, the victims of higher costs and fewer maintenance men.

Chief horticulturist Lindsay said when the price of one chrysanthemum went to 75 cents a few years ago (compared to a few cents for pansies and tulips) he ordered the park service to cut back gradually on the 90,000 it was planting.

"And nobody noticed" he said.

Now, instead of automatically replacing perfectly good marigolds, petunias and scarlet sage with the mums, the gardners will plant the fall flowers only in "high visibility" areas.

This fall there will be 1,250 mums at Farragut Square, 1,350 at McPherson Square and 3,320 at Lafayette Square.

The 50,000 to 75,000 roses that once graced the park in front of Union Station have dwindled to 2,000 because "roses require so much maintenance and we don't have the manpower," Lindsay said. The number of gardeners, for instance,has dropped from 120 in the early 1970s to approximately 85 today. f

Azaleas, which require a good deal of attention, have suffered a similar fate. Many have been replaced with shurbs, Lindsay said, though some will continue to bloom at McPherson Square, along Independence Avenue and at other sites.

"I try not to do the same thing in a park twice," Brady said. "If I put marigolds on Maine Avenue [near the Jefferson Memorial] then I put in scarlet sage the following year."

He not only rotates flowers among the 43 parks he oversees, but he also makes sure one bed does not stay the same color from April to October.

"You don't want to take out red tulips and put in red marigolds, If I put in yellow tulips I want to try to follow with red geraniums or begonias or a mix and then a white mum."

Washington became a pageant of petals when former First Lady Lady Bird Johnson started her beautification program in the mid-1960s.

"We used to have half as many flowers as we have now and a lot of shrubs, but Lady Bird changed all that," recalled Brady, who has spent 20 years with the Park Service.

"All those little triangles and squares now have flowers. We didn't have any daffodils until she came and now they're all along the highways that the Park Service controls."

Since then, the Park Service has also developed a "library" of 7,100 flowers on Independence Avenue near the Tidal Basin where people can find out the botanical name of the flowers they have seen around the city.

It also is where Lindsay is experimenting with different varieties of amaryllis, ornamental onions and anemones. If they prosper, they will be in the parks in 1982. CAPTION: Pictures 1 and 2, Van Brady, who planted star magnolias for the side of the Jefferson Memorial . . . . . . also designed this color scheme of crocuses and daffodils in Potomac Park. Photos by Margaret Thomas -- The Washington Post