"They asked if I would prepare a bouquet of her favorite flowers and meet him downstairs so he could take them to her," she said.
Politics can also come into play when it comes to floral presentations. Clarke has received briefings from the State Department on foreign flower protocol.
"Oh, yes," she said, "because in some countries, like Muslim countries, for example, you wouldn't have white flowers. Those are very funereal flowers. So, you're very careful."
Clarke will especially miss Christmas time at the White House. The flower shop is responsible for all of the elaborate decorations, such as wreaths, ornaments and trees.
Planning for the December holiday usually begins right after Easter. Preparations already are underway for the Obama's first holiday season.
Even after three decades, the majesty of working at the White House has yet to fade.
"When I come in and I drive past the outside of the White House, because it's dark when I get here, and I can see the flag with the lights on it, I mean, it's overwhelming," she said, "It never gets old."