Often, the problem has to do with pruning at the wrong time. I would skip pruning your Opening Day Viburnum for a couple of years. Let it get back on track with growing and forming flower buds. In a couple of years when you do prune it, prune late winter or early spring. Also, be certain it is getting plenty of sun. And, when fertilizing, don’t give it too much nitrogen. Nitrogen will grow leaves. Phosphorous helps viburnums flower.
Thanks for writing!