date hierarchy

Are Date Heirarchies available for DateTime fields created via the PowerBi API?

I would like to be able to group my bar charts by year, month, etc. 

I have a 'Push' dataset created via the API. I have tables with 'Datetime' columns. In the Service GUI, when I add the date columns to the Axis section of a Bar Chart, it does not provide a Date Hierarchy. 

I am confident that the column type is 'Datetime'.

I tried changing the column type to 'Date' but it is not supported by the API. 

Calculated columns (such as one that would automatically create the Year, Month, etc) are also not supported by the API. 

I tried sending new data with only the date portion, but PBI still tranformed it into a date time (ie. it added the time portion).