Probably you are familiar with the Mother Goose nursery rhyme "Daffy Down Dilly."
Daffy Down Dilly
Has come to town,
In a yellow petticoat
And a green gown.
Children's author Bethany Roberts has compiled this rhyme and so many others on her web page.
Here's one about a daffodil:
A little yellow cup
A little yellow frill,
A little yellow star,
And that's a daffodil.
And here are several more anonymous rhymes:
Close your eyes
And I'll rub spring across your cheek,
Soft as velvet, smooth and sleek.
Close your eyes and do not peek.
There was a dandelion
With lovely fluffy hair
That glistened in the sunshine,
And in the summer air.
And oh! This pretty dandelion
Soon grew old and grey,
And sad to tell!! Her charming hair,
Blew many miles away.