Once I've wrapped floral clay down the stem of the bouquet holder, I build up a thicker band about half way down the bouquet holder.
True hand tied bouquets are created in a spiral pattern, which causes the stems to splay outwards from the neck of the bouquet. Building up a thicker band of clay in the center will cause the cut stems to flare out in the same pattern.
Press the cleaned stems gently up into the clay at the top of the handle and then press lightly against the center mound of clay.
Continue to add more and more stems, while revolving the bouquet holder around in your hands.
This is how the stems will begin to look. Note that you can still see the bouquet handle in the center. Continue to add stems until the handle is completely concealed.