Alternatively, you can get the dome a table base and a large rose and a vase.  Drill a hole in the bottom of the vase and through the table base.  Get a large straw and some expanding foam or sand or floral foam.  place the straw upright in the vase and through the hole in the bottom.  Fill the vase with expanding foam or sand.  You are temporily going to pull the rose petals off the rose and attach invisible thread or light weight fishing line to each petal with hot glue, by sewing, or superglue.  Now reattach the petals to the rose, reinforce the stem of the rose with wire and place the stem of the rose about 2-3" away from the straw in the foam or the sand--make sure it is firmly inplace.  Next thread all the fishing lines through the straw.  A stage hand  under the table base pulls each thread one at a time to make the petals drop.

 

Before the next show the petals are reattached.

 

Or... you can also have a video projected on the wall of the rose with petals falling, or a shadow projection of it.