Let the sunshine in!

I can’t get this unknown song out of my head:

When the violets bloom
the birds flock
then I want to go far away.
If the stream is free of ice,
the lilac shines white, 
then nothing keeps me in the dark house.
laughs the sun in the blue,
you only feel the wind lukewarm
and a scent holds the heart spellbound,
there a butterfly easily
gently stroking over fields,
Yes, spring has now come to the land.

And right after – like a hymn:

Let the sunshine, let the sunshine in, the sunshine in…