The conservatories were torn down in 1902 to make way for the modern "West Wing" offices (and to allow the entirety of the existing White House to hold Theodore Roosevelt's large family), but by then, flowers were firmly established as essential to the White House routine.
In addition to selecting flowers in the colors and designs preferred by Presidents and First Ladies, the White House Florists have had to read up on the international meanings of flowers, and how they relate to the customs of visiting dignitaries. If, for example, in a certain country, a specific flower is traditionally used only in funeral arrangements, that flower would not make a great centerpiece for a state dinner.
While styles have changed over the years, from the formal "roundy moundy" displays favored by Jacqueline Kennedy to the "gardenesque" looks requested by Michelle Obama, flowers have remained front and center at the White House, and every resident, including Presidents and First Ladies, have had their favorites.
Here are some flowers that played memorable parts in White House events, and tips for growing them yourself:
Nancy Clarke, the White House Chief Floral Designer for 25 years, recounted in her book, My First Ladies, that Nancy Reagan's favorite flowers were white peonies, and that she constantly had to remind Mrs. Reagan that peonies were only available in the spring.