What is the meaning of Frost's Fragmentary Blue?

I came across this poem and was wondering what it means.





Here's the poem:


Why make so much of fragmentary blue


In here and there a bird, or butterfly,


Or flower, or wearing-stone, or open eye,


When heaven presents in sheets the solid hue?


Since earth is earth, perhaps, not heaven (as yet)--


Though some savants make earth include the sky;


And blue so far above us comes so high,


It only gives our wish for blue a whet.