Your quilt is beautiful. I agree with Janet. I think a motif of some sort would look great in the setting triangles with cross hatching in the background. Here is a link to a lonestar quilt I did like this with a motif and simple cross hatching in the background in the setting triangles and squares.
http://www.quiltingboard.com/t-22341-1.htm
Maybe you could use your dogwood stencil there.
For the border a cable would look great or maybe a continuous vine and leaf motif to carry on your floral theme. There are some beautiful stencils offered by the stencil company and I think the cable and flower border would be so pretty! It comes in several widths.
http://quiltingstencils.com/viewallborders.aspx