The descending blue

Of all the images that come with Christmas, the one that's been in my mind this time is that of a seed. A tiny seed sprung from another world, struck into our old soil. Breaking through it, growing to fruit and shade - graft, and gift. So, rather than a poem of bleak midwinter, or Christmastide, it's Hopkins' “Spring” that I think of today. 

Nothing is so beautiful as spring—
When weeds, in wheels, shoot long and lovely and lush;
Thrush's eggs look little low heavens, and thrush
Through the echoing timber does so rinse and wring
The ear, it strikes like lightnings to hear him sing;
The glassy peartree leaves and blooms, they brush
The descending blue; that blue is all in a rush
With richness; the racing lambs too have fair their fling. 
What is all this juice and all this joy?
A strain of the earth's sweet being in the beginning
In Eden garden.—Have, get, before it cloy,
Before it cloud, Christ, lord, and sour with sinning,
Innocent mind and Mayday in girl and boy,
Most, O maid's child, thy choice and worthy the winning.