This expression alludes to a daisy reopening its petals in the early morning or to its welcome appearance in springtime. The freshness of daisies has been a literary commonplace since at least the late 14th century when it was used by Chaucer.
RELATED IDIOMS :
be fresh out of something
have just sold or run out of a supply of something - informal
break fresh ground
do something innovative which is considered an advance or positive benefit
Literally, to break new ground is to do preparatory digging or other work prior to building or planting something. In North America the idiom is break ground.
a breath of fresh air
a small amount of or a brief time in the fresh air
new or younger members of a group especially those admitted as an invigorating force