When does a white Dogwood tree start to bloom? Dogwood shows no signs of blooming yet.
White Dogwood Bloom Time
Certified GKH Gardening Expert
In general your Dogwood should bloom for a 10 day to 2 week period in the time frame of April to May.
Is this a newly planted tree, or a more established tree?
Are you concerned your tree may have died?
Are the branches pliable or do they snap off?
Doing a scratch test on the tree can help determine if a tree is alive or dead.
Here are some links with more information.