Hi Star! I think this is explained best on Mary Moth's great encasing tutorial! She uses stringers but the exact same principle applies when using larger rods. Here's the link:
http://www.wetcanvas.com/Articles2/24464/484/
And here's the main idea she explains with "chasing out air":
"When melting in your layer of encasing, do not rapidly spin the bead in a super hot flame. If you do this, you could possibly be trapping air in the channels made between your wraps of glass.
Instead, heat from one side of the bead to the other while slowly turning. This 'chases' any air trapped between your wraps of clear and lets them escape. Once you get the feel for wrapping the glass, you'll learn to remove trapped air while melting it all in."
Don't give up on the florals... it takes a LOT of practice but there are so many avenues to explore!