Q. What year was the ecology recycling theme with a huge hanging mobile made from plastic milk jugs
There was an exhibit in 1995 by Wayne Reed Davis "A Recycled Garden Valentine" made of cutout milk bottle pieces.
If this is not the exhibit you are thinking of, you can revisit Flower Show memories by going through the Flower Show programs that were produced in the 1990s.
and click on links to the 1990s Flower Show programs. Find the table of contents and go to the pages of Major Exhibitors for that year. Have fun!