Inch by Inch; the Garden Song by David Mallett. It's an older book with nice big illustrations. I found a great Youtube video of John Denver singing it on the Muppet show here. I also read, My Garden by Kevin Henkes. Here is a flannelboard rhyme I made up a few years ago.
Flowers Grow In Flowerpots
(by Kathryn Roach)
Here are 10 flowerpots ready for some fun.
I'll sit them outside in the bright warm sun.
(we say the color of the pot as I put it on the board)
I have 10 flower seeds that need a spot!
I'll plant each of them in a color flowerpot.
(we count as I put the 10 seeds in the pots)
Each little seed will grow to be,
A beautiful flower for all to see!
(I place matching flowers to pots with kid's help)
With sunshine* and water* the seeds can grow
Into 10 pretty flowers.
See my lovely flower show!
(* = add sun and raincloud)
I also sang The Flower Song by Nancy Stewart, with the kids. I printed, cut out and mounted on green construction paper squares, Google images for a daffodil, yellow rose, tulip and iris. I laminated them and handed them out and we 'planted' each flower as the song played. They were careful to keep the squares in nice rows! I always identify the flowers before we sing and this time the children started to call out the kind they wanted. I've trained them though to be happy with what they get by the little rhyme...(they can say it with me)..."Take what you get, and don't pitch a fit!". There's usually a lot of laughing as we say that rhyme together. Actually, as I handed out the cards they were excited and showed each other what they had. When the song was over and they saw the flannelboard full of flowers they were happy and proud. I'm so glad spring is here!