Sheffield sells the seed. This is their comment.

These seeds are collected from mother trees with white flowers. A high percentage of the resulting seedlings will also have white flowers. Even as seedlings the white-flowered trees can be told from the red flowered trees due to their lighter colored leaves.

Thanks so much!

based on that ... the only question left.. is how many years you are going to have to grow the tree to maturity to verify the white flowers ... just guessing.. 5 to 7 years...

the species.. seeds around my yard rather easily... so i doubt you will have much problem getting some result in actually sprouting trees ...

in my MI .... the vermin break the pods .... seeds fall .. and they sprout in spring ... so dont go making it all too complicated ..... dont fight what might easy ...

of course.. i dont know where you are .. so i cant go on from there

worse case scenario ... you give a year old seedling away .... and your friend call you back in 5 to 7 years... lol .. to let you know the flower color ... not a bad investment .. friend-wise ...

ken