Working at night, head nurseryman Paul Thiene supervised the planting of plants, shrubs, trees and vines. He made sure that their colors were complementary and that their growth was uniform. In case some of the plants failed to bloom, Thiene kept about 10,000 geraniums ready for replacement in the nursery.

The El Prado symphony of green vines and bright flowers climbing over soft white walls, of florid sculptured ornament around building openings, and of striped blue and orange draperies hanging from doors and windows delighted spectators. Red bougainvillea pranced along El Prado while purple bougainvillea danced in the Plaza de Panama. Clipped black acacias in front of buildings imposed order on the riotous blooms.