How do you keep bees from cross polinating the plants?
Bees
Remove the anthers from all the flowers or tape the blooms shut.
My two cents worth about hybridizing. If you really want to make sure that you have a pure cross of ? x ?, then you need to collect pollen from an unopened bud and place the pollen on an unopened bud, then seal the mother, pollen receiver. Only by doing this can you be close to 100 percent sure of your cross. Both bees and insects can contaiminate the dad and mom to be. Most hybridizers are concerned with the mother, but the dad could be effected also. You could also seal off both before their buds open and as somme as you apply the pollen to the mother, reseal her.
Larry