Answer: Based on your description it is difficult to make a specific suggestion. Since one has bloomed well, I think your care must be adequate. However, it is possible one has rooted and established better than the other due to a difference in soil conditions. Or, if they were seedling grown, there may be a variation between them in terms of maturity and blooming ability. Or, one may be in better light than the other. This type of dogwood needs at least a half day of sun to bloom well -- it is not as shade tolerant as the native Cornus florida.
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