And when I asked Ian:
as for casting/ molding dandelions.. jeezz.. you can make one time use plaster molds the facing half of a flower by laying the flower down and mixing plaster and putting it on quite thin when it goes creamy, not going past the center line of the half. when this sets carefully - tweezers - pull all the flower bits out and you can then dampen the plaster and put in hot wax, when it sets up cut away excess and you have wax of half the flower.. can then take this wax and use it for a lost wax casting technique..
My friend, Faith, is good with making molds and she said that she'd help me.