Thanks Fred.
My E.japonicum is now in bud, but not open, but previous years someone has eaten the flower and I haven't gotten any seeds from it. I don't know if it is possible to get seeds from just one plant..
I have sprinkled used coffee powder around Erythroniums hoping that it smells so bad and voles don't come near my plants. So far it has worked, and I hope my plants stay untouched.