I did my best:
The little flowers, they sleep long ago in the moonlight, They nod their heads on their tiny stems. The blossom tree is shaking, he purrs like a dream. Sleep sleep, sleep calm my little child.
The little birds, they sang so sweetly in the sunshine, they have gone to rest in their small nests. The crickets in the cornfields are chirping: Sleep sleep, sleep calm my little child.
Sandman comes sneaking and peeping through the little window, if still a sweetheart may not be in bed. And where he finds an awake child, he scatters sleepsand into the eye. Sleep sleep, sleep calm my little child.
Sandman out of the room, it sleeps purely my dear, there is even firmly closed already the eyes. It lights me tomorrow; welcome 'the little eyes so pious! Sleep sleep sleep calm my little child.
I know not every phrase is in correct english but I don't know how to correctly translate it. I hope you can understand the text.