Question - why aren't these propagated plants blooming. I can explain the one that is planted in my neighbors yard, and the closest pollenator is 300 feet away. But not sure about the others. Seed propagated plants should bloom - right?

Lack of blooming would be associated with not enough sun or too young. It has nothing to do with how close another viburnum/pollinator is. Yes, seed propagated plants should bloom given the right sun conditions and age. The first two seem to get plenty of sun, so it might be age ... or do you have deer that might nibble the tips? Or perhaps your nursery plants are older than you think and were pruned at some point. Your seedlings just might not be old enough.

Lack of fruit would be associated with either no blooms (of course) or poor pollination. Assuming you can get blooms, you should be able to get pollination if your original plants are setting fruit. The parents do still set fruit, right?

You can always add other viburnums to your collection. If you get ones that bloom at the same time, that can only enhance your eventual cross pollination success. It doesn't have to be more v. dilatatum plants, other species that bloom at the same time would help. I have a V. dentatum 'Blue Muffin' and V. acerifolium that help each other set fruit.

The parents are blooming and producing lots of fruit. The plant that is the closest to the parent that is in 7 hrs of sun is at least 5-6 yrs old, probably more. It grew from a seedling and now is about 6ft h x 4-5ft wide. It is growing very well. I just assumed that by now it would be blooming better - there have been a few sporatic blooms. I guess that is a start!
I just bought two new viburnum dentatum's that I can add to the collection - so will see it that helps - Thanks Mike

V. dentatums won't pollinate V. dilatatums.

V. dentatums won't pollinate V. dilatatums

laceyvail, I know you must have some reason for saying that. If you could be more specific, I think it would help others understand better.

As I've said, I have v. acerifolium and v. dentatum cross pollinate each other, so it can't just be an interspecies thing. Do the bloom times not overlap on v. dentatum and v. dilatatum? Of course that would prevent cross pollination. If the bloom time can overlap, is it a physical limitation between the v. dilatatum species and others?

Could it be possible that because these plants were propagated from seeds rather than cuttings that these plants did have good flower characteristics?