Apparently with no surprise,
To any happy Flower,
The Frost beheads it at its play,
In accidental power.
The blond assassin passes on.
The sun proceeds unmoved,
To measure off another day,
For an approving God.
The Frost is now being called an “assassin”, reinforcing the idea that it is a metaphor for Death. 
 It may be described as “blonde” to describe the sunlight that will melt it away in the next line.
Apparently with no Surprise