I don't see why you couldn't plant two in the same hole......but really no need. Like other members of its genus, Cornus mas is self-fertile - it does not require a pollination partner. However, you do tend to get heavier cropping with a second clone available.

we have all seen two plants in one hole... from bird dropped fruit.. to 2 acorns ... to two seeds with annuals ... [or a thousand maples in a gutter.. lol ...]

imo ... that is not an issue .. as long as both plants are basically equivalent with future growth potential ... obviously.. if one will dwarf and outgrow another.. forcing it into shade ... then that one might not thrive.. nor be much of a pollinator for the huge one.. lol

ken

I have visions of branches rubbing and constant pruning.

tj

Like ken said it doesn’t really happen that way. Every tree on my four acre property that is planted clos or next to another the two trees act as one, if you step back and look one trees growt is on one side and the other tree on the other side. There will be crossing branches but no more so than you get branches crossing from a single tree

Thanks for the input!