Sang as a Girl Scout in Connectut during 1950's as a round.
1. White coral bells upon s slender stalk.
2. Lilies of the valley deck my garden walk.
3. Oh don't you wish that you could hear them ring.
4. That will only happen when the fairies sing.

Heuchera is called coral bells and comes in white variety. Lily of the valley is a different species.

I think the lyrics clearly have origin in an English speaking country. Melody origin could be different.

One of my favorite songs from childhood.