For a number of years we couldnt provide a White H x orientalis. Some of the problem stemmed from the  fact that the spotting in hellebores can be quite dominant and all our plants ended up White Spotted. We have now bred one line that is giving us a good pure White and another that provides fine spotting.  The flowers are also quite rounded. As with many hellebore flowers, the White fades to green on maturity. Same rules apply when it comes to siting the White Hybrid. Plenty of organic mulch, sun isnt an issue if there is some shade at the days hottest time, but most importantly, dont plant in a site that isn't free draining.