Rosalie Sorrels has a great one about her grandmother's gardens. though they both had different styles of gardening, one more random, the other quite orderly, they both grew Bells of Ireland. The chorus goes:

These are the Bells Of Ireland hat in my garden grow
My great grandmother brought those seeds From Ireland long ago
Their music it is sweet and sad Like orphan angels sing
If you listen in your heart you'll hear Those Bells of Ireland ring.....

I always like to sing it with White Coral Bells....

oh, don't you wish that you could hear them ring?
that will only happen when the fairies sing.

also Kate Wolf has a beautiful tune she did Acapella about The Lilac Bush and the Apple tree...

Greg Brown also does a tune for Ani DeFranco called "Vivid" in which she brings him flowers

and what about Malvina Reynolds one (seems to be based on a Ferlenghetti poem?) about the sunflower growing thru the cracks in the sidewalk ["God Bless the Grass"?]---

and then there is Rosalie Sorrels who does a tune directly from Ferlinghetti--"La Bruja, Flower of Revolution"...she has both that one and another on her borderline heart album: Ken Kesey's "Ragweed Ruth"...

and someone MUST have written a line or two featuring that famous photo form (was it?) Kent State where the anti-war protester slid daisies down the barrel of the national guard soldier....

laurie Lewis also has one: "When the Cactus is in Bloom".

and has no one yet mentioned Dolly Parton's Wildflowers.