Here you can see the how to.
According to it I prepared a yarn from one green and two yellow sacks. One plastic bag gives up to about ten meters.
Just in a short - you take a bag, fold it several times in a vertical direction, cut off the handles and the bottom and chop the rest into strips. These unfolded make circles that are to be joined with a knot together to form a double yarn.
Here you can see how I enlarged yarn when crocheting. This is the knot - very easy.
This is a little blossom that came into being. To be sincere the photo is much nicer than the flower itself:-P The flash is something..
As far as the crochet, the leaves are all the same - I made a chain, than one round of stitches back, one around this to the tip of the leaf and back again. This round consists of stitches from the smallest ones to the big ones and back. Upwardly the stitches are: slip stitch, single crochet, half double crochet, double crochet and double treblecrochet. The spirals - I made a long chain and single crochets back.