Why does Wordsworth use daffodils as a key word in "I Wandered Lonely as a Cloud"?

The poem is based on an experience Wordsworth had when he saw a full field of daffodils while walking with his sister Dorothy. In essence, then, this is a factual poem, although Wordsworth transforms the view into a personal revelation not shared with anyone else. Daffodils are among the showiest and most noticeable flowers of spring. Their yellow hues pop out from the surrounding green grass and leaves of the season. The narrator enjoys the way they sway and dance whenever the wind blows across the field. They seem to say that winter is over, and that color and life have returned to the landscape. Seeing the daffodils improves Wordsworth's mood, both in the moment and then later, when he pictures the scene again. The daffodils represent life and some of the best parts of it.