First, here's the real thing:
The leaves are like rosemary...
...and the flowers are on a squared-off stalk at the end of the stem.
Pinch it all the way around on each corner. If you stick the oval into a toothpick it would be easier to hold it while you pinch the nubs onto it. I realized that too late, so I didn't do it, but it would work better if you did. Pinch two little petals on opposing sides on the top of the flower, then two smaller ones on the other sides.
Make a bunch of flowers with different petal sizes and thicknesses.
If you haven't already, insert a toothpick into the base of the flower. Paint dark purple food coloring on the nubs and the petals at the top.
Paint a lighter purple in the centers of the flower between the nubs. You should be able to see a little of the green through the purple and at the base of the flower.
For the stems, roll out some green gumpaste very thin and let a piece about 3" long dry.
For the leaves, roll out some tiny sausages of green gumpaste and press a vein into it using a flat tool like the back of a knife or a toothpick.
Do a bunch of these, up to twenty per stem, and let them dry.
To attach the leave to the stems, put the dried stems on parchment or waxed paper and cover the base with melted green candy melts. Layer the leaves onto the stem, starting at the top and working your way down the stem.
When the candy melts have hardened up, remove the stems from the parchment and insert the flower onto the stem. You may have to enlarge the hole in the flower by digging out some of the gumpaste with the end of the toothpick. For this method of making lavender you will probably need to leave it lying against the cake on the icing because the stems are so thin they may not support the weight of the flowers on their own. If you want to substitute floral wire for the stem you can do that so that there's more support for the flower.
Dust some sage green petal dust all over the stems and leaves to make the color of the gumpaste and modelling chocolate uniform.
Kara Buntin owns A Cake To Remember LLC, custom wedding cakes in Richmond VA